hmmm maybe the way it works is a little different than i first thought, let me reframe it.

ofc you can still use Ninjutsu after Mudras, but when you got Forked Raiju, Ninjutsu (which is otherwise disabled) turns into Forked Raiju, forked Raiju also stacks so it doesn't need to be used right after Raiton, was it different before? i swear i couldn't use Forked Raiju anymore if i didnt use it right after Raiton.