As for why Reaction Commands are making a return, Nomura said, “After the release of Kingdom Hearts 3 we saw a lot of requests for the return of the reaction command, so we brought it back.”
Reaction Commands were famous in Kingdom Hearts 2 – and follow-ups like Kingdom Hearts: Birth by Sleep – for extending combos and performing special actions.
Among the many changes in combat, director Tetsuya Nomura has confirmed the return of a fan-favorite feature – Reaction Commands.
Square Enix shocked many fans (and non-fans) when it announced a new mainline Kingdom Hearts title.