Strong characters that would be shit-tier in a fighting game due to their mechanics

This thought popped into my head while i was thinking about Rien from Limbus Company (dude lives rent free in my head at this point).

His 'weapon' is a little canister of liquid metal that takes the shape of one of nine weapons, except he doesn't know which one it's going to be until it's already out. It isn't random exactly, it's controlled by the Prescript (aka God) but he isn't told what he's going to get each time he swings. He could go for a piercing thrust and get a whip, try a wide crowd-clearing swing and get a dagger, etc.

Despite this, he is still considered a serious threat in canon. But it made me think, this guy would be absolute dogshit in a fighting game if his gimmick was translated 1:1. Imagine every attack you throw out has a randomly selected hitbox and frame-data. Want a quick jab to break your opponent's combo? Here's a 25 frame startup. Eat shit.