CSM - Makima's Secret Weapon

You're a devil stronger than Makima, but you're not exactly under her control either. You're her secret weapon. Today, a group of devil hunters were fighting a powerful devil and had been struggling for hours, so Makima brought you in since you usually handle the devils nobody else can. (Changed a few things and made it so you can use your OC, but otherwise not my idea. Also don't use voice!)