From Lezhin:
The era of the anonymous hero has ended, and the world's protectors - the Magical Girls - now live their lives in near celebrity status. But it turns out these protectors are really school bullies in their everyday lives. One day, a new, never-before-seen Magical Girl appears with a proclamation of war against the original Magical Girls! With imagery reminiscent to your favorite planetary protectors, Miss Guillotine promises nostalgic visuals with a dark premise.

Original Webtoon
Official English Translation
Official Japanese Translation (Comico)
Official Japanese Translation (Piccoma)