Good Loser Kumagawa (グッドルーザー球磨川, Guddo Rūzā Kumagawa) is a special chapter of the series Medaka Box. It appeared in Shueisha's Jump Next, and featured Misogi Kumagawa as the main character. The chapter was later included in Volume Fifteen. It is the first part of the sub-series, Good Loser Kumagawa Gaiden.
Two months prior to his arrival at Hakoniwa Academy, Kumagawa transfers into Suisou Academy. When the other students laugh at his joke of having transferred from Weekly Shōnen Jump, he attacks the entire class with his screws, only to undo the damage an instant later. This terrifies the whole class. Kumagawa is later approached by Sukinasaki; that she would start a conversation with him makes him happy enough to start crying. He listens as Sukinasaki describes the school's Student Council president and monarch, Jakago. After hearing of her Abnormality, Kumagawa agrees to meet with her, commenting that it might be just the skill he is looking for.
Jakago welcomes Kumagawa to the academy in her office; Kumagawa mentions what he has heard of her, an act that horrifies Sukinasaki. Aware of who must have told him, Jakago demonstrates her ability on Sukinasaki, suffocating her, and driving the girl to her knees. Kumagawa panics, crying out that his childhood friend from age two is going to die (parodying the relationship between Medaka and Zenkichi). He begs Jakago to stop, who compiles, and asks Sukinasaki if she is sorry, to which the other girl tearfully says she is. She then offers Kumagawa her hand, only to withdraw it before he can shake hands with her. He asks her if anything is wrong, and after she replies in the negative, dismisses him. Renpei questions Jakago if they should take out Kumagawa before he cause any problems, but is shot down, Jakago claiming she would rather cut her own throat than shake hands with him. She notices that Sukinsaki is still present, and tells her she may leave. Sukinasaki takes direct control of the members of the Student Council. Declaring that she was the one who made Jakago Student Council president, she labels Kumagawa as too dangerous to be left alone. Removing her mask and revealing a deranged smirk, she declares herself the most important, as her skill allows her to control other skill holders.
Kumagawa is later surrounded by the Student Council in an empty classroom. Speech slurred, Jakago tells him she is going to force him to leave. Kumagawa easily sees that they are being controlled, and expresses his derision of Jakago's ability, calling it a skill that can be defeated simply by holding one's breath. Kumagawa is shocked however, when his screws crumble. Jakago reveals that she has oxidized both his weapons and his body, and Kumagawa collapses. As the other members of the Student Council argue, she tells them to stop, then questions why they are all staring behind her. She turns around, and is horrified to find that Kumagwa has gotten back to his feet. Kumagawa tells Jakago that while her skill is enough to control humans, it is not enough to control non-humans; she won't be able to defeat Anshin'in. When the Student Council asks who Anshin'in is, he tells them that she is a what, not a who. Kumagawa then orders them to show their skills, though he does not expect much as he has already overcome their leader. He defeats all four in an instant, then explains his Minus to Jakago, claiming that they are the ones at fault for being controlled. Jakago falls to her knees upon hearing Kumagawa's explanation of his Minus, and questions why he is looking for other skill holders when he is already so powerful. Kumagawa explains that even his Minus is not enough to defeat Anshin'in, and he is looking for other skill holders for just that purpose. He then tells her to leave, giving her five seconds before he changes his mind. He attacks after one second anyway, claiming that he changed his mind about the time limit. As Jakago calls him a liar before collapsing, Kumagawa agrees with her, telling her to remember the name of his Minus, All Fiction.
The next day, Kumagawa is approached by Sukinasaki, who tells him that Jakago "overworked" herself, and has been hospitalized. She recommends he become Student Council president, as he has no prior history within the school. When Kumagawa tries to turn her down, Sukinasaki reveals that she has taken control of all their classmates. Giving in, Kumagawa admits that he has lost to her. One month later, Suisou Academy is shut down, due to the conclusion of the battle between Kumagawa and Sukinasaki, a battle with no winner.
Characters in Order of Appearance
*Note: Bold = First Appearance