Who is the character of idaten jump?

I'll just list all the characters:

Boys:

Sho Yamato

Kyoichi Shido

Koei

Arthur

Gabu Samejima

Taiga Samejima

Kakeru Sakamaki

Ayumu Yamato

Girls:

Makoto Shido

Ms Yuki

Nagi Saniguma(er... my own character)

Kiku