Hentai Kamen

Literally Perverted Mask, Ultimate!! Hentai Kamen is a 6 volume manga by Keishuu Ando. Mild-mannered Kenpo specialist Kyosuke accidentally puts a pair of panties rather than a robbers mask on when he tries to sneak in and spoil a robbery. His mother's 'perverted blood' awakes within him, he strips, and the baddies are toast. Hijinks ensue.

Contains examples of:

 * Accidental Pervert : Often. It doesn't help that I Just Want to Be Normal Kyosuke has inherited his mom's S&M-lovin' genes...Come to think of it, it was an Accidental Pervert incident that created Hentai Kamen to begin with.
 * Badass Normal: Kyosuke becomes increasingly the most normal person (as his normal persona) with strength, although this starts to drain near the end.
 * Calling Your Attacks: Subverted, averted, inverted, lampshaded, and turned upside down. "Inferno Bullet Train", anyone?
 * Cool Mask: Subverted so hard that it makes your head hurt.
 * Covert Pervert / Chivalrous Pervert: Kyousuke, Tengu Maru. Kamen is definitely the latter, using less gross techniques on women - although he's rarely in a position to fight them to begin with. He also can't figure out why people pass out when he walks so close...
 * Fridge Logic: Kyosuke's powers can't activate when he wears his mom's underwear, since they're related. However, his infant son's powers manifest when his own mother's underwear falls onto his face. What? It may be because supposedly Kyosuke's power comes from his mother's side of the family...
 * Man in a Bikini: The titular mankini wearing/wielding hero of justice.
 * Oh Crap: The usual expression of people who're about to go in to Kamen's underwear, face-first.
 * Only Sane Man: Kyosuke and Aiko; mostly the former.
 * Punch-Punch-Punch Uh-Oh: The tournament, with the 100 Erupting Horsefly fists...getting tangled in Hentai Kamen's underwear straps.*
 * Running Gag: Several; people's heads caught in Kamen's underwear (leading to facefaults/fainting from spectators); Shunka trying to pass off something good of Shuto's for something bad of hers, and then wrapping her brother's head in a large version of whatever it is when he corrects her; Aiko's crazy strength when it comes to Kyousuke; the Captain attacking, getting Ishida to root for him - only to realized that he's hitting on the opponent.
 * Ship Tease: Kyosuke/Aiko, Kyosuke/Shunka. He marries the  in the end.
 * Spell My Name with an "S": Kyosuke's name has a drawn-out 'o' sound, so it's just as good to spell it Kyousuke, Kyohsuke, Kyoosuke, etc.
 * Widget Series: If the plot didn't tip you off that this series is a widget, then nothing will.
 * X Meets Y: Captain Underpants, but with panties.