Sekihiko Inui: 4 books

Shuto Katsuragi is a superhero otaku. Only problem is, he's too short and always getting teased for his height...especially when he tries to emulate his favorite superhero! To make matters worse, Shuto suddenly gets abducted and tricked into participating in some rather sketchy and super-villainous experiments!

Despite having been tricked into helping a bunch of weirdo villains, Shuto still hasn't given up on his dream of being a hero. Determined to prove his worth as a crime fighter, he starts going after bad guys on his own, with mixed results. And things really get complicated when Shuto is invited to...

When Shuto is knocked unconcious during his battle with the hero Ankaiser, Ratman's innate abilites take over and pummel his opponent. During his recovery later, Shuto is wracked with doubt over his new heroic role. When it seems that his idyllic view of the world of heroism was just an illusion, what's a would-be super hero to do?

What should have been an easy caper for Ratman goes south when a mysterious hero claiming to be from a secret, elite section of the Hero Association--called "Sector S"--appears. Unable even to scratch this new hero, Shuto is mercilessly beaten down, and the drubbing was enough to ruin his confidence...