I've really been enjoying this game and its probably my favorite take on single player fighting game experience. I Think I've done pretty much everything in the game besides catching all the fish. However I can't for the life of me figure out how to unlock Matsu as an assist without using debugging tools. I've noticed that the samurai at the far right of the map uses her as an assist but I genuinely think I've tried everything my smooth brain can think of with this lead. I was wondering if I was missing something or if she's even obtainable legitimately at this point in the game.
P.s. I've been playing this game using my arcade stick and I just wanted to add that it feels great!