I was trying to find an answer to this, but I couldn't find anything so I'm making this thread for any questions people might have regarding the combat systems in P4G.
What determines when "fusion skills" are used and how many are there in the game, exactly? Before I replaced Chie with Kanji, Yukiko and Chie would infrequently perform this move after the main character's turn:
Is it randomly after the player pulls off a critical move or hits an enemy's weakness or is there something else? Also, how many of these skills are there in the game? With my final team composition of main character, Yosuke, Yukiko and Kanji, I never saw anything like this again.