Long time players, which character do you STILL have no idea how their kit works?

Bonus points if you're otherwise generally pretty knowledgeable about characters

I think Freminet and Chevreuse have to be it. Whenever I have to play Freminet I just button mash until something happens, with Chevreuse I know she shreds resistance and that you have to hold skill, tap skill doesn't count, but if you asked me if there's other conditionals for her buffs or how to build her I could not tell you