He has a complicated relationship with Medaka, saying that he hates her while also idolizing her in a way, as his biggest wish was to defeat her and prove himself better. Despite his awful circumstances, Kumagawa is almost always seen wearing a large smile. His biggest wish is to win against the 'main characters', who are better than him at everything. He is the type of person who seriously considered erasing everyone in the world, including himself.
Because of his circumstances, he has developed a completely twisted personality, having little empathy for others and simply erasing what he doesn't want to deal with using All Fiction. Kumagawa is the most negative person in the world, one who has never won anything in his life.
