<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by Broadridge Transform (tm) - http://www.broadridge.com -->
<!-- Created: Thu Sep 03 19:13:45 UTC 2026 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ConsolidatedBalanceSheet" roleURI="http://www.t3dfns.com./role/ConsolidatedBalanceSheet"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ConsolidatedIncomeStatement" roleURI="http://www.t3dfns.com./role/ConsolidatedIncomeStatement"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ConsolidatedComprehensiveIncome" roleURI="http://www.t3dfns.com./role/ConsolidatedComprehensiveIncome"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ConsolidatedCashFlow" roleURI="http://www.t3dfns.com./role/ConsolidatedCashFlow"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ConsolidatedCashFlowAlt1" roleURI="http://www.t3dfns.com./role/ConsolidatedCashFlowAlt1"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ScheduleofFairValueofAssetsAcquiredandLiabilitiesAssumedFollowingtheAdjustmentsMentionedTable" roleURI="http://www.t3dfns.com./role/ScheduleofFairValueofAssetsAcquiredandLiabilitiesAssumedFollowingtheAdjustmentsMentionedTable"/>
  <roleRef xlink:type="simple" xlink:href="dfns-20260630.xsd#dfns_r_ScheduleofEffectofDeconsolidationTable" roleURI="http://www.t3dfns.com./role/ScheduleofEffectofDeconsolidationTable"/>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ConsolidatedBalanceSheet" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_CashAndCashEquivalentsConsolidatedVariableInterestEntity" xlink:href="dfns-20260630.xsd#dfns_CashAndCashEquivalentsConsolidatedVariableInterestEntity"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="dfns_CashAndCashEquivalentsConsolidatedVariableInterestEntity" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_OtherCurrentAssetsConsolidatedVariableInterestEntity" xlink:href="dfns-20260630.xsd#dfns_OtherCurrentAssetsConsolidatedVariableInterestEntity"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="dfns_OtherCurrentAssetsConsolidatedVariableInterestEntity" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RestrictedCashCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_RestrictedCashCurrent" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MarketableSecuritiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MarketableSecuritiesCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_MarketableSecuritiesCurrent" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InventoryNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_InventoryNet" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NotesAndLoansReceivableNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableNetCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_NotesAndLoansReceivableNetCurrent" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherReceivablesNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_OtherReceivablesNetCurrent" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsReceivableNetCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AccountsReceivableNetCurrent" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_OtherAssetsCurrent" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LoanGranted" xlink:href="dfns-20260630.xsd#dfns_LoanGranted"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="dfns_LoanGranted" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent" order="12" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrent"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetsHeldInTrustNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsHeldInTrustNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_AssetsHeldInTrustNoncurrent" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_OtherAssetsNoncurrent" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EquityMethodInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_EquityMethodInvestments" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_Goodwill" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherIntangibleAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_OtherIntangibleAssetsNet" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanGovernmentsRightsToPlanAssetsInEventOfPlanTerminationAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanGovernmentsRightsToPlanAssetsInEventOfPlanTerminationAmount"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_DefinedBenefitPlanGovernmentsRightsToPlanAssetsInEventOfPlanTerminationAmount" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_NonCurrentAssetsOfConsolidatedVariableInterestEntitiesOne" xlink:href="dfns-20260630.xsd#dfns_NonCurrentAssetsOfConsolidatedVariableInterestEntitiesOne"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="dfns_NonCurrentAssetsOfConsolidatedVariableInterestEntitiesOne" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAssetsNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsNoncurrent" xlink:to="us-gaap_DisposalGroupIncludingDiscontinuedOperationAssetsNoncurrent" order="12" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent" order="1" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsNoncurrent" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShortTermBorrowings" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermBorrowings"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_ShortTermBorrowings" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccountsPayableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_AccountsPayableCurrent" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_NotesPayableCurrent" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_DueToRelatedParties" xlink:href="dfns-20260630.xsd#dfns_DueToRelatedParties"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="dfns_DueToRelatedParties" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_OtherLiabilitiesCurrent" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_OtherCurrentLiabilitiesOfConsolidatedVariableInterestEntities" xlink:href="dfns-20260630.xsd#dfns_OtherCurrentLiabilitiesOfConsolidatedVariableInterestEntities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="dfns_OtherCurrentLiabilitiesOfConsolidatedVariableInterestEntities" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LoansPayableFormerRelatedPartiesCurrent" xlink:href="dfns-20260630.xsd#dfns_LoansPayableFormerRelatedPartiesCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="dfns_LoansPayableFormerRelatedPartiesCurrent" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_StockPurchaseWarrantLiabilities" xlink:href="dfns-20260630.xsd#dfns_StockPurchaseWarrantLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="dfns_StockPurchaseWarrantLiabilities" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_DeferredConsiderations" xlink:href="dfns-20260630.xsd#dfns_DeferredConsiderations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="dfns_DeferredConsiderations" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ConvertibleNotesPayableCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleNotesPayableCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_ConvertibleNotesPayableCurrent" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NotesPayableToBankCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableToBankCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_NotesPayableToBankCurrent" order="12" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DerivativeLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_DerivativeLiabilitiesCurrent" order="13" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent" order="14" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LoanPayableFormerRelatedPartiesNetOfCurrentPortion" xlink:href="dfns-20260630.xsd#dfns_LoanPayableFormerRelatedPartiesNetOfCurrentPortion"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="dfns_LoanPayableFormerRelatedPartiesNetOfCurrentPortion" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LiabilityInRespectOfEmployeeRightsUponTermination" xlink:href="dfns-20260630.xsd#dfns_LiabilityInRespectOfEmployeeRightsUponTermination"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="dfns_LiabilityInRespectOfEmployeeRightsUponTermination" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="us-gaap_DeferredIncomeTaxLiabilitiesNet" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesNoncurrent" xlink:to="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Liabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_LiabilitiesCurrent" order="1" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_LiabilitiesNoncurrent" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PreferredStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_PreferredStockValue" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CommonStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_CommonStockValue" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_StockholdersEquity" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_MinorityInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_MinorityInterest" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_TemporaryEquityCarryingAmountAttributableToParent" order="2" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" order="3" weight="1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ConsolidatedIncomeStatement" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_GrossProfit" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Revenues" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_Revenues" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CostOfRevenue" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfRevenue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_CostOfRevenue" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_ResearchAndDevelopmentExpense" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_SellingAndMarketingExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingAndMarketingExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_SellingAndMarketingExpense" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_GeneralAndAdministrativeExpense" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_GeneralAndAdministrativeExpensesOfConsolidatedVariableInterestEntities" xlink:href="dfns-20260630.xsd#dfns_GeneralAndAdministrativeExpensesOfConsolidatedVariableInterestEntities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="dfns_GeneralAndAdministrativeExpensesOfConsolidatedVariableInterestEntities" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_AssetImpairmentCharges" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_GrossProfit" order="1" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingExpenses" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <loc xlink:type="locator" xlink:label="dfns_InterestIncomeOfConsolidatedVariableInterestEntities" xlink:href="dfns-20260630.xsd#dfns_InterestIncomeOfConsolidatedVariableInterestEntities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_InterestIncomeOfConsolidatedVariableInterestEntities" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeInFairValueConvertibleNote" xlink:href="dfns-20260630.xsd#dfns_ChangeInFairValueConvertibleNote"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_ChangeInFairValueConvertibleNote" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeInFairValueStockPurchaseWarrantLiabilities" xlink:href="dfns-20260630.xsd#dfns_ChangeInFairValueStockPurchaseWarrantLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_ChangeInFairValueStockPurchaseWarrantLiabilities" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_GainOnSettlementOfVendorObligations" xlink:href="dfns-20260630.xsd#dfns_GainOnSettlementOfVendorObligations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_GainOnSettlementOfVendorObligations" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnSharesIssuedAsCommitmentForELOCAgreement" xlink:href="dfns-20260630.xsd#dfns_LossOnSharesIssuedAsCommitmentForELOCAgreement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_LossOnSharesIssuedAsCommitmentForELOCAgreement" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_GainOnSettlementOfDueToAffiliates" xlink:href="dfns-20260630.xsd#dfns_GainOnSettlementOfDueToAffiliates"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_GainOnSettlementOfDueToAffiliates" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_DayOneLossOfStockPurchaseWarrantsIssuedInConnectionWithConversionOfConvertibleNotes" xlink:href="dfns-20260630.xsd#dfns_DayOneLossOfStockPurchaseWarrantsIssuedInConnectionWithConversionOfConvertibleNotes"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_DayOneLossOfStockPurchaseWarrantsIssuedInConnectionWithConversionOfConvertibleNotes" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_DayOneLossOnPrivatePlacement" xlink:href="dfns-20260630.xsd#dfns_DayOneLossOnPrivatePlacement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_DayOneLossOnPrivatePlacement" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_OtherIncome" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InterestExpenseNonoperating" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_InterestExpenseNonoperating" order="12" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_InterestExpenseDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_InterestExpenseDebt" order="13" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnMarketableSecurities" xlink:href="dfns-20260630.xsd#dfns_LossOnMarketableSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_LossOnMarketableSecurities" order="14" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_PenaltyLateRegistration" xlink:href="dfns-20260630.xsd#dfns_PenaltyLateRegistration"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_PenaltyLateRegistration" order="15" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_FinancialExpenseNet" xlink:href="dfns-20260630.xsd#dfns_FinancialExpenseNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_FinancialExpenseNet" order="16" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnSettlementOfVendorObligations" xlink:href="dfns-20260630.xsd#dfns_LossOnSettlementOfVendorObligations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_LossOnSettlementOfVendorObligations" order="17" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_PenaltiesOnLateRegistration" xlink:href="dfns-20260630.xsd#dfns_PenaltiesOnLateRegistration"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="dfns_PenaltiesOnLateRegistration" order="18" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_OperatingIncomeLoss" order="1" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_NonoperatingIncomeExpense" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperations" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperations" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_IncomeLossFromContinuingOperations" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_NetIncomeLossFromDiscontinuedOperations" xlink:href="dfns-20260630.xsd#dfns_NetIncomeLossFromDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="dfns_NetIncomeLossFromDiscontinuedOperations" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <loc xlink:type="locator" xlink:label="dfns_NetIncomeLossAttributabletoParent" xlink:href="dfns-20260630.xsd#dfns_NetIncomeLossAttributabletoParent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="dfns_NetIncomeLossAttributabletoParent" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" order="2" weight="1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ConsolidatedComprehensiveIncome" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_ProfitLoss" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentTax" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_ComprehensiveIncomeNetOfTaxIncludingPortionsAttributableToNoncontrollingInterest" xlink:href="dfns-20260630.xsd#dfns_ComprehensiveIncomeNetOfTaxIncludingPortionsAttributableToNoncontrollingInterest"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_ComprehensiveIncomeNetOfTaxIncludingPortionsAttributableToNoncontrollingInterest" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_ComprehensiveIncomeNetOfTaxIncludingPortionsAttributableToNoncontrollingInterest" xlink:to="us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" order="2" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ConsolidatedCashFlow" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_ProfitLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_IncomeLossFromContinuingOperations" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncomeLossFromContinuingOperations" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Depreciation" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_Depreciation" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_ShareBasedCompensation" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeInFairValueConvertibleNoteEmbeddedDerivative" xlink:href="dfns-20260630.xsd#dfns_ChangeInFairValueConvertibleNoteEmbeddedDerivative"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_ChangeInFairValueConvertibleNoteEmbeddedDerivative" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeinFairValueStockPurchaseWarrantLiabilities" xlink:href="dfns-20260630.xsd#dfns_ChangeinFairValueStockPurchaseWarrantLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_ChangeinFairValueStockPurchaseWarrantLiabilities" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInDueToRelatedParties" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDueToRelatedParties"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInDueToRelatedParties" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_IncreaseDecreaseInInventorys" xlink:href="dfns-20260630.xsd#dfns_IncreaseDecreaseInInventorys"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_IncreaseDecreaseInInventorys" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInDueToAffiliates" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDueToAffiliates"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInDueToAffiliates" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInterestPayableNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInInterestPayableNet" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_AmortizationOfDebtDiscountPremium" order="12" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnSettlementOfVendorObligations" xlink:href="dfns-20260630.xsd#dfns_LossOnSettlementOfVendorObligations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_LossOnSettlementOfVendorObligations" order="13" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetImpairmentCharges"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_AssetImpairmentCharges" order="14" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnExtinguishmentOfConvertibleNotesPayable" xlink:href="dfns-20260630.xsd#dfns_LossOnExtinguishmentOfConvertibleNotesPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_LossOnExtinguishmentOfConvertibleNotesPayable" order="15" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" order="16" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SharesIssuedAsPartOfSettlementAgreement" xlink:href="dfns-20260630.xsd#dfns_SharesIssuedAsPartOfSettlementAgreement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_SharesIssuedAsPartOfSettlementAgreement" order="17" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SharesIssuedAsPenaltyForFiling" xlink:href="dfns-20260630.xsd#dfns_SharesIssuedAsPenaltyForFiling"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_SharesIssuedAsPenaltyForFiling" order="18" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SharesIssuedAsCommitmentForEquityLineOfCreditAgreement" xlink:href="dfns-20260630.xsd#dfns_SharesIssuedAsCommitmentForEquityLineOfCreditAgreement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_SharesIssuedAsCommitmentForEquityLineOfCreditAgreement" order="19" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeInFairValueOfLiabilityclassifiedStockPurchaseWarrants" xlink:href="dfns-20260630.xsd#dfns_ChangeInFairValueOfLiabilityclassifiedStockPurchaseWarrants"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_ChangeInFairValueOfLiabilityclassifiedStockPurchaseWarrants" order="20" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInDerivativeLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDerivativeLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInDerivativeLiabilities" order="21" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_InterestEarnedOnMarketableSecuritiesHeldInTrustAccount" xlink:href="dfns-20260630.xsd#dfns_InterestEarnedOnMarketableSecuritiesHeldInTrustAccount"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_InterestEarnedOnMarketableSecuritiesHeldInTrustAccount" order="22" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_EmployeeExtermination" xlink:href="dfns-20260630.xsd#dfns_EmployeeExtermination"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_EmployeeExtermination" order="23" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_ChangeInDeferredTaxes" xlink:href="dfns-20260630.xsd#dfns_ChangeInDeferredTaxes"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_ChangeInDeferredTaxes" order="24" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_InterestOnLoans" xlink:href="dfns-20260630.xsd#dfns_InterestOnLoans"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_InterestOnLoans" order="25" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainOrLossOnSaleOfStockInSubsidiary" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainOrLossOnSaleOfStockInSubsidiary"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_GainOrLossOnSaleOfStockInSubsidiary" order="26" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_GainnMarketableSecurities" xlink:href="dfns-20260630.xsd#dfns_GainnMarketableSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_GainnMarketableSecurities" order="27" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_IncreaseDecreaseInLeaseAssetsAndLeaseLiabilities" xlink:href="dfns-20260630.xsd#dfns_IncreaseDecreaseInLeaseAssetsAndLeaseLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_IncreaseDecreaseInLeaseAssetsAndLeaseLiabilities" order="28" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable" order="29" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherCurrentAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_IncreaseDecreaseInOtherCurrentAssets" order="30" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_GainOnSettlementOfVendorObligations" xlink:href="dfns-20260630.xsd#dfns_GainOnSettlementOfVendorObligations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_GainOnSettlementOfVendorObligations" order="31" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_GainOnSettlementOfDueToAffiliates" xlink:href="dfns-20260630.xsd#dfns_GainOnSettlementOfDueToAffiliates"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_GainOnSettlementOfDueToAffiliates" order="32" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_GainLossOnSaleOfBusiness" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="us-gaap_GainLossOnSaleOfBusiness" order="33" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_DayOneLossonStockPurchaseWarrantsIssuedinConnectionwithPrivatePlacement" xlink:href="dfns-20260630.xsd#dfns_DayOneLossonStockPurchaseWarrantsIssuedinConnectionwithPrivatePlacement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_DayOneLossonStockPurchaseWarrantsIssuedinConnectionwithPrivatePlacement" order="34" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_LossOnReclassificationOfStockPurchaseWarrantsFromEquityclassifiedToLiabilityclassified" xlink:href="dfns-20260630.xsd#dfns_LossOnReclassificationOfStockPurchaseWarrantsFromEquityclassifiedToLiabilityclassified"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:to="dfns_LossOnReclassificationOfStockPurchaseWarrantsFromEquityclassifiedToLiabilityclassified" order="35" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities" order="1" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities" order="2" weight="1"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsDisposalGroupIncludingDiscontinuedOperations" order="5" weight="1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ConsolidatedCashFlowAlt1" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <loc xlink:type="locator" xlink:label="dfns_ShortTermDepositInInvestingActivities" xlink:href="dfns-20260630.xsd#dfns_ShortTermDepositInInvestingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="dfns_ShortTermDepositInInvestingActivities" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromPaymentsForTradingSecurities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromPaymentsForTradingSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_ProceedsFromPaymentsForTradingSecurities" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_AdvanceToTargetOfPlannedAcquisition" xlink:href="dfns-20260630.xsd#dfns_AdvanceToTargetOfPlannedAcquisition"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="dfns_AdvanceToTargetOfPlannedAcquisition" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleOfShortTermInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfShortTermInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_ProceedsFromSaleOfShortTermInvestments" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ProceedsFromInvestmentInShortTermSecurities" xlink:href="dfns-20260630.xsd#dfns_ProceedsFromInvestmentInShortTermSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="dfns_ProceedsFromInvestmentInShortTermSecurities" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" order="7" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_PaymentToAcquireDeconsolidationOfSubsidiary" xlink:href="dfns-20260630.xsd#dfns_PaymentToAcquireDeconsolidationOfSubsidiary"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="dfns_PaymentToAcquireDeconsolidationOfSubsidiary" order="8" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_PaymentsToAcquireInterestInSubsidiary" xlink:href="dfns-20260630.xsd#dfns_PaymentsToAcquireInterestInSubsidiary"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="dfns_PaymentsToAcquireInterestInSubsidiary" order="9" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" order="10" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireLoansReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireLoansReceivable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_PaymentsToAcquireLoansReceivable" order="11" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireOtherInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_PaymentsToAcquireOtherInvestments" order="12" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" order="13" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromRelatedPartyDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromRelatedPartyDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromRelatedPartyDebt" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ProceedsFromInvestmentOfMinorityInSubsidiary" xlink:href="dfns-20260630.xsd#dfns_ProceedsFromInvestmentOfMinorityInSubsidiary"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_ProceedsFromInvestmentOfMinorityInSubsidiary" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromLinesOfCredit" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromLinesOfCredit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromLinesOfCredit" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_BusinessCombinationNetOfIssuanceCosts" xlink:href="dfns-20260630.xsd#dfns_BusinessCombinationNetOfIssuanceCosts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_BusinessCombinationNetOfIssuanceCosts" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ProceedsFromIssuanceOfPrivatePlacementAndEmbeddedDerivativeNetOfIssuanceCosts" xlink:href="dfns-20260630.xsd#dfns_ProceedsFromIssuanceOfPrivatePlacementAndEmbeddedDerivativeNetOfIssuanceCosts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_ProceedsFromIssuanceOfPrivatePlacementAndEmbeddedDerivativeNetOfIssuanceCosts" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_ProceedsFromSaleOfSPACUnitsAndPrivatePlacementUnitsNetOfIssuanceCosts" xlink:href="dfns-20260630.xsd#dfns_ProceedsFromSaleOfSPACUnitsAndPrivatePlacementUnitsNetOfIssuanceCosts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_ProceedsFromSaleOfSPACUnitsAndPrivatePlacementUnitsNetOfIssuanceCosts" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromNotesPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromNotesPayable" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfWarrants" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromIssuanceOfWarrants" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromIssuanceOfDebt" order="11" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" order="12" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RepaymentsOfShortTermDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfShortTermDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_RepaymentsOfShortTermDebt" order="13" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RepaymentsOfNotesPayable" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfNotesPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_RepaymentsOfNotesPayable" order="14" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_PaymentsOfLoanCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfLoanCosts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_PaymentsOfLoanCosts" order="15" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_RepaymentsOfLoans" xlink:href="dfns-20260630.xsd#dfns_RepaymentsOfLoans"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_RepaymentsOfLoans" order="16" weight="-1"/>
    <loc xlink:type="locator" xlink:label="dfns_PaymentOfLiabilityToFormerShareholderOfASubsidiary" xlink:href="dfns-20260630.xsd#dfns_PaymentOfLiabilityToFormerShareholderOfASubsidiary"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="dfns_PaymentOfLiabilityToFormerShareholderOfASubsidiary" order="17" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_RepaymentsOfRelatedPartyDebt" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfRelatedPartyDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_RepaymentsOfRelatedPartyDebt" order="18" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ScheduleofFairValueofAssetsAcquiredandLiabilitiesAssumedFollowingtheAdjustmentsMentionedTable" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <loc xlink:type="locator" xlink:label="dfns_BusinessCombinationRecognizedIdentifiableWorkingCapitalexcludingCashAndCashEquivalents" xlink:href="dfns-20260630.xsd#dfns_BusinessCombinationRecognizedIdentifiableWorkingCapitalexcludingCashAndCashEquivalents"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="dfns_BusinessCombinationRecognizedIdentifiableWorkingCapitalexcludingCashAndCashEquivalents" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentAssets" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_BusinessCombinationRecognizedIdentifiableIntangibleAssetsOfAvailableForSaleNet" xlink:href="dfns-20260630.xsd#dfns_BusinessCombinationRecognizedIdentifiableIntangibleAssetsOfAvailableForSaleNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="dfns_BusinessCombinationRecognizedIdentifiableIntangibleAssetsOfAvailableForSaleNet" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_Goodwill" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_Goodwill" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_BusinessCombinationAcquisitionNoncontrollingInterest" xlink:href="dfns-20260630.xsd#dfns_BusinessCombinationAcquisitionNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="dfns_BusinessCombinationAcquisitionNoncontrollingInterest" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="7" weight="-1"/>
    <loc xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities" order="8" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:role="http://www.t3dfns.com./role/ScheduleofEffectofDeconsolidationTable" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:href="dfns-20260630.xsd#dfns_NetCashProvidedByDeconsolidationOfSubsidiary"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationWorkingCapitalexcludingCashAndCashEquivalent" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationWorkingCapitalexcludingCashAndCashEquivalent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationWorkingCapitalexcludingCashAndCashEquivalent" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationInvestmentInInvestee" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationInvestmentInInvestee"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationInvestmentInInvestee" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationOtherCurrentAssets" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationOtherCurrentAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationOtherCurrentAssets" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationInvestmentUnderTheFairValueOption" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationInvestmentUnderTheFairValueOption"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationInvestmentUnderTheFairValueOption" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationTangibleAssets" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationTangibleAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationTangibleAssets" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationLoanFromTheCompany" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationLoanFromTheCompany"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationLoanFromTheCompany" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:label="dfns_SubsidiariesDeconsolidationNoncontrollingInterest" xlink:href="dfns-20260630.xsd#dfns_SubsidiariesDeconsolidationNoncontrollingInterest"/>
<!-- [WMV7][ImLGvLhiiDf08Ms/vwVwM6cXH5cKrNxIS+2cLkGRVnr3TTuXOGdwtB+qyOWB4f4DcENoQ630OA6/7ixVH56bTMxqO6CDq4mMV1FHd6dUL05RB46rZxUTNUHXlSGKoqCwjwFgua94lsToIDcnHCVeaoxtrAf23rzA2kLI4DgWcIddwWRLrXLkrfrULTeGoj7Ad9/ZEkMmcD7ej3fvTDYFHdFWWuykCXXKYepAqD3iJ4Ljr6xumFI3rhrovbzcwjVxMfQ9Vn0Vc6JqFekNdi1NkkuhBfISllnYTpGSJ+srZowyQDr9tCaptLXHJgI+RPC28qo0YQ==] CSR-->
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="dfns_NetCashProvidedByDeconsolidationOfSubsidiary" xlink:to="dfns_SubsidiariesDeconsolidationNoncontrollingInterest" order="7" weight="1"/>
  </calculationLink>
</linkbase>
