Doujin in the context of "Clique"

Hentai (Japanese: ヘンタイ) is a style of Japanese pornographic anime and manga. In addition to anime and manga, hentai works exist in a variety of media, including artwork and video games (commonly known as eroge).

The development of hentai has been influenced by Japanese cultural and historical attitudes toward sexuality. Hentai works, which are often self-published, form a significant portion of the market for doujin works, including doujinshi. Numerous subgenres exist depicting a variety of sexual acts and relationships, as well as novel fetishes.

Doujinshi (同人誌), also romanized as dōjinshi, is the Japanese term for self-published print works, such as magazines, manga, and novels. Part of a wider category of doujin (self-published) works, doujinshi are often derivative of existing works and created by amateurs, though some professional artists participate in order to publish material outside the regular industry.

Groups of doujinshi artists refer to themselves as a sākuru (サークル, circle). Several such groups actually consist of a single artist: they are sometimes called kojin sākuru (個人サークル, personal circles).