ANGEL BEATS! THE 4-KOMA: OSORA NO SHINDA SEKAI KARA

Proper Japanese Title: Angel Beats! The 4コマ お空の死んだ世界から Originally serialized in Dengeki G's Magazine. — Description from Comic Vine community (comicvine.gamespot.com · https://comicvine.gamespot.com/angel-beats-the-4-koma-osora-no-shinda-sekai-kara/4050-96698/).