Ano Ko wa Toshi Densetsu.

There is an urban legend about a girl, Zangyaku-san, who is sort of a death god who gives out punishment to lolicons. She goes around punishing lolicons everywhere and puts them into an eternal state of sleep while also taking away their souls.

She happens to meet a lolicon but she is not able to give out her punishment properly to him. And the second time too he narrowly escapes the punishment. But after that incident this lolicon decides to have his revenge as she insulted him by calling him a "Fake Lolicon."

The story proceeds as he is finally able to enter her realm and have his revenge and we are then led to ride a roller coaster of emotions.