Hentai seiyoku translates roughly to “abnormal sexual desires.” During the Meiji period (1857-1912), this was a branch of Japanese sexology. metamorphosis (as in the change from caterpillar to butterfly).Western fans often use H and hentai interchangeably. Hentai only refers to sexual situations that are considered perverse and fantastic: bizarre partners and gang rape, for example. H (pronounced as etchi or ecchi) and ero refer to any manga and anime with sexual content. The word nōmaru is sometimes used as an antonym for hentai. Hentai describes a sub-genre of erotic literature rather than all erotic literature. The word hentai is a compound word that describes a person, action, or state of being sexually abnormal. Hentai has a long history and conflicted definitions. Hentai is as valid a branch of manga and anime as shonen and shojo.
Yep, I am going there! Some information here may be considered graphic.