Warashibe is a college student who is infatuated with Miho Nosaka, and is good at Capsule Monster Chess. He has a habit of sucking lollipops.

He tried desperately to gain Miho's attention by giving her several Capsule monster pieces, but Miho never understood that he loved her. Warashibe pretended to be a hero in front of Miho by saving her from a guy, who was really Yugi in disguise. However Miho recognized Yugi the moment she saw him, even with a bag over his head. Also Warashibe's appearance (meaning how he looked) didn't meet her expectations. Warashibe tried to invite Miho to his secret base, but she refused and slapped him after getting too creeped out. Embarrassed by what happened, Warashibe poisoned Miho's friends with unboiled water, thus prompting her confront him. She located Yugi, whom she then forced to lead her to Warashibe's base.

Eventually, he forced her to play a game of Capsule Monster Chess against him. If she won, he promised to stop following her. But if she lost, she was to 'fufill her destiny' and be with him. Upon realizing that Warashibe had rigged the dispenser to give her the weaker monsters, of a level one and two variety, Miho got up to leave. Warashibe refused to let them leave, as he wanted to put Miho in a giant CapMon capsule. He quickly closed his gate, which broke, causing a part of it to hit Miho and Yugi.

Yugi changed to Dark Yugi, who then challenges Warashibe to a Capsule monsters Shadow game. Yugi wins, and Warashibe imagines himself captured in a Capsule monsters capsule as his penalty game.