Shoto Todoroki not only has his fire and ice quirk but he also has a Yandere quirk that causes him to want to harm or kill anyone who dares to get near the person he loves. He thought he liked Momo but he never really felt anything for her. And one day, he knew why he never felt anything for her. It was always Izuku. He loved Izuku to the point that he would kill anyone and anything that got in his way or tried to hurt Izuku.