Datenshi Koumori-kun no Junai

First-year high school girl Riku Shiraha is reunited with her childhood friend Mitsumori-kun after six years, and she finds his "bad boy" persona to be strangely alluring for some reason!? A love story woven with you, my childhood friend — who was once so angelic — now fallen into darkness.

(Source: Palcy, translated)