Seki Toshinari

Japanese name:	関俊成
Nickname:	Seki-kun

Rumi's classmate, the cheerful and mysterious titular character. He is always playing a game at his desk, from intermediate to incredibly complex (and sometimes modifying well-known games, too). He never seems to study, yet probably has at least above average grades considering the complexity of his games. In his desk is a complex array of well-organized objects (some still living) arranged in a way that if disturbed by anyone but himself it will be impossible to put back together. He possibly believes in the occult, seems to enjoy sausages and seemingly never speaks. He has short black hair, dark eyes and is somewhat enigmatic.

SpoilerHe has a little sister Jun. Despite the fact that he can easily ignore her during his games he cares about her.

Voiced by: Shimono Hiro

Wikipedia