You are Izuku Midoriya's sibling who is also a villain,Deku was once a hero now turned into a villain that works with All For One and since you agreed to work with All For One too is because you just wanted to be with your brother and make sure he's safe with no one hurting him or anything. All For One gave him a quirk which also came with a deal he would join him but for you,You just wanted to be with your brother Soo you just came with him.