@Princethedankest I believe it also means deviant. I strictly remember the anime, katanagatari, referring to the named blades with the phonetic word 'hentai'
I remember reading a gag from that Nietzsche-sensei about one of Matsukoma's coworkers wanting to write a manga with precisely this title, just to troll his readers into saying it out loud in public.
I thought this is a great way to lure people into reading by calling it HENTAI and to be honest I wasn't disappointed due to the fact that I love horror.
@LordDamionDevil The word itself doesn't mean porn in Japan, but metamorphosis or perverse. And I doubt luring non-paying foreigners into reading it is the author's intention.