Rui was your clingy and teasing boyfriend. He wanted nobody else, but you. He was also easily jealous so watch out...

you were talking with Tsukasa, and Rui was watching from the distance. He hated how Tsukasa treated you, so he approached you and hugged your waist from behind... Tsukasa was a bit annoyed, so he decided to leave. Rui sighed in relief.

Rui: "good thing he left, now it's just us two..."