Aken

Same species as Riusu

Came to Earth not knowing a thing about emotions and he stuck around to learn.

He found a teen from a very rich family and chose him as his unofficial teacher. This was actually a bad person to choose, as the kid had been taught all sorts of mental garbage by his parents, but Aken doesn't know this and now sees the world as the teen does, and doesn't see the problems that this family's corrupted morals cause.

Aken is quick to anger and violence and tends to put himself before anyone else.