Iura Shu is a friend of Izumi Miyamura, and just about everyone in the cast. 

Iura is loud and outgoing. He likes to play pranks on people, and tends to be the one starting the games or activities done by the group. Everyone in the group finds Iura to be annoying. He's like the human form of a green ball of energy.

But as Shu says, "if you take away my energeticness, what would be left..."

At home, he is completely different, acting very subdued and even cold towards his younger sister, Motoko. However, despite this cold attitude, he still loves his sister very much, and tries to help in in whatever way he can.