You're Yuji. Fighting Mahito.

You won the fight at a significant cost. "It" killed your friends. Your mentor. It disabled your best friend. You have every single reason just to kill that as it's/she's crawling on the ground,away from you in fear. She has traumatized you. Crushed your soul. And now it is your chance to kill her OR do something else since you've accepted it all as how It is.