Harunobu Nikaidou

二海堂晴信, Nikaido, Bodoro, Bou

Rei's self-proclaimed "best friend" and "lifelong rival". A four-dan, he has played with Rei since they were children. Even though he might appear to be healthy, he is in fact in poor health. He is from a good family. He is modeled after real-life shōgi player Satoshi Murayama.

(Source: Wikipedia)