Lomon

When a boy falls to his death at school his twin sister, Ok Chan Mi, does not believe that it is suicide. She transfers to Yongtan High, the school in question and meets a witness to her brother's death. When a bully-hunter also shows up at the school, Chan Mi suspects that it may be connected to her brother's death, and looks for this potential ally. (disney+)

A high school becomes ground zero for a zombie virus outbreak. Trapped students must fight their way out or turn into one of the rabid infected.

Ho Goo-hee, a high schooler and self-proclaimed pushover, discovers a new application on her phone that offers to take revenge on anyone whose name she writes in it. (wikipedia)