Weak Hero Class 2

Once the bullies target you, it’s game over. The school is run by tyrants whose favorite hobby is tormenting the weakest kids in class. But then Shi Eun arrived. This mysterious new student threatens to dismantle the established order. He may be small in stature, but his calculative and brutal fighting leaves unsuspecting opponents lying on the floor begging for mercy. Now the school's toughest bullies have to scramble to take down this new and unusual hero.
(Source: webtoons.com)
~~ Adapted from the webtoon “Weak Hero” (약한영웅) written by SeoPass and illustrated by Kim Jin Seok.