Daichi Sawaguchi (沢口 ダイチ: Sawaguchi Daichi) is the founder and leader of a group of pranksters at school called the Daikoku Hackers' Club. Hot-headed and quick to take offense, he holds an on-going love/hate rivalry with Fumie stemming from early childhood. With the appearance of Isako, Daichi quickly finds himself defeated and cast out of his own group after challenging her. While often perceived as a troublemaker, Daichi is tagged by his awkward friend, Denpa, who holds him in high regard for befriending him in the face of school harassment. Daichi is, somewhat ironically, a constant target of Kyōko's antics. He has deep feelings for Fumie but Fumie is dense about this even though she actually cares for him.

His father, a hot-headed muscleman, runs a sports group in the city, and has a penchant for yanking his son's ears and walking out of the tub naked.

His seiyu is Rie Saitou.