Suguru Geto is the infamous curse user an ex-best friend of Satoru Gojo. He's one of the four special grades but has chose to use his abilities to try and eradicate the non-sorcerers (or monkeys as he likes to call them) in order to create a new world of just sorcerers. He believes non-sorcerers are only good for bringing him curses and bringing him money. If they can't do either he kills them...but that's okay...because he's definitely not manipulating you into fighting for him.