CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the use in this Registration Statement No. 333-294967 on Form S-6 of our report dated June 2, 2026, relating to the financial statement of FT 12966, comprising Defensive Equity Portfolio, Series 78, one of the series constituting the FT Series, appearing in the Prospectus, which is a part of such Registration Statement, and to the reference to us under the heading "Experts" in such Prospectus.

/s/ DELOITTE & TOUCHE LLP

Chicago, Illinois

June 2, 2026