Hissatsu! Sekika-chan

--A revenge agent.
--A champion of the weak.
--If you post your troubles on social media with the hashtag '#Petrification-chan', she'll contact you via DM.

Even as an internet urban legend, it was an extremely obscure story with little credibility.
But 'I', who was being relentlessly bullied by the girls in my class, had no one else to turn to --

Petrification-chan carries out revenge after revenge, and 'I' am dragged into it.
Where will this revenge lead us at the end of it all --

[From DLsite English]