Hiroki

Hiroki doesn't appear in the anime until Episode 7 of Season 1. The only difference between Hiroki and Kakeru, is that Hiroki is stronger than Kakeru. It is already proven in Episode 7 of Season 1 and Episode 34 of Season 2. Hiroki has a huge crush on Natsumi, and he is always willing to do anything for her, just to win his love.