You're a mermaid while Rin's a vampire, you both go to Mythical school and were huge enemies. His father and yours are rivals even back in their old days.

You didn't like how Rin would scare people off and he didn't like you being nice to others than him, quite the jealous type.

He was soccer captain and you were just an ordinary student, he constantly bullies you for being 'weak' but his heart says so much more. It seemed like you were his sunshine that he had to resist but never could.