Kaiten!!

Kaiten!! is a one-shot manga written and illustrated by Katsura Hoshino. It was published in the magazine Jump Square in october 2011.

Summary
In Japan, many evil organizations terrorize the people and the police can't do anything. One of them, Gamshack is composed of supernatural beings called Kaijins. A member of Gamshack called Shiropaya decides to resign from the job as she doesn't want to be a villain anymore but rather a hero.

She searches a job among the heroes squadrons with poor results when a kaijin attacks. He is defeated by a costumed man called Red who happens to be very stressed.

She is explained by a old lady that the boy: Red Koutarou suffers from a very rare illness but is a very good hero, though alone in his squadron. Shiropaya decides to join his squadron to help him fight the crime.