Shu is the older brother of Kurumi Momose, however, even he cannot resist calling Kurumi "plain" from time to time. Shu is a laid-back character and a skilled cook. He helps his often drunk and irresponsible homeroom teacher, Miyuki Igarashi, take care of class 1-A. Also, he can be easily persuaded into doing things, like when asked to prepare Becky's lunch for her everyday or when during that time be persuaded to take a day off. This can make him seem like a guy that also succumbs to pressure, especially that of a group, as in episode 4 when he was told to prepare a bath for all of the girls and didn't even complain about it.

(source:Wikipedia)