Doujinshi

From Kokorodatabase

Coming from the fandom dimension, doujinshi are fan comics ("manga") created and published by usually non-professional artists and writers, sometimes collaborating in "circles" (or groups). Doujinshi may be sold at special doujinshi conventions, anime/manga/game conventions, and in some stores. They have become a fearsome and quite brainbreaking thing in the Kokoro world. Kuroneko Satou, however, likes to collect it to give away, and Kiki Reikaira keeps a secret collection in her closet, which Ryou has found (somehow, without triggering the various traps around the closet) and used as blackmail.