Gantz O (2016)
While fighting invading monsters, Kei Kurono rescues his friend, Reika. Though she protests, he faces off against the monsters’ leader, dying just after killing it. Reika and her surviving teammates are teleported back to their base. Elsewhere, Masaru Kato dies after attempting to save someone from a knife-wielding man. He wakes up in a small room with Reika and her teammates: Yoshikazu Suzuki, an old man; Joichiro Nishi, a surly teenager; and an angry, unidentified man. Suzuki explains that, in the past, they have each died and woken in the room. They are subsequently forced to fight against waves of monsters. Before Suzuki can explain further, a black orb they identify as Gantz announces their next mission is about to begin. The angry man defiantly refuses to participate, and Nishi kills him, reasoning that he will be a liability.
