Main chasers from .Flow.
They are schoolchildren whose uniform consists of black shoes, black trousers, a white shirt and a red necktie.
They seem to be of both genders, but Lol (Artist) has stated that all of them are female. They share some characteristics as Pale Skin and white hair, with blood on their faces.
In-game, there are three different kaibutsu wich in turn have two sets of sprites, one for their "sane" state and other for their "insane" state, which looks as if they had suffered severe injuries to their faces.