Gantz manga volume 4 contains volumes 10-12 in an omnibus format and features story and art by Hiroya Oku.

Kei Kurono’s work as a Gantz alien fighter is a hellish nightmare, but his life as a high-school student is looking up, with a new ladylove opening his heart. But when his beloved is threatened by a Gantz-obsessed schoolmate on a shooting rampage, Kei must face the murderous student without his Gantz suit for protection!