Hentai Kamen was released in Japan in April. I offer no explanation. But TwitchFilm does, and in “Review: HENTAI KAMEN Delivers A Face Full Of Crotch” they say:
(…) When the object of Kyousuke’s affection, Aiko, is taken hostage in a bank robbery, it’s up to the smitten student to rescue her.
In attempting to disguise himself as one of the masked criminals the boy accidentally picks up a pair of girl’s panties, pulls them over this head and – too late to realize his mistake – breaths deep of the panty odour.
A transformation occurs and he becomes the super-powered, and utterly perverted super-hero, Hentai Kamen (Pervert Mask). Exploding onto the screen wearing nothing but a pair of very skimpy white speedos he proceeds to beat the crooks with an assortment of extreme sexual poses and martial arts / wrestling moves that always leave the villains with a face full of crotch. (… read more, twitchfilm.com)
I actually started reading the comic after seeing the trailer for this film. I gotta say, I haven’t laughed so hard in a long, long time. It’s that mix of perverted-but-still-somehow-cute that only the Japanese can do.