Hiroki  

In the anime series, Hiroki does not make an appearance until episode seven of season one. Although there are some differences between him and Kakeru, it's important to note that Hiroki is stronger than Kakeru. This has been established in episodes seven of season one and thirty-four of season two. It's worth mentioning that Hiroki harbors a massive crush on Natsumi and is willing to do anything to win her affection.