Ryouta Sugimoto

Ryouta behaves as a frightened child abruptly separated from any ordinary sense of safety. He stays close to his grandmother and relies on her judgment throughout the mission.

He has neither the maturity nor experience to understand Gantz's rules, making Kayo's efforts to protect him essential.

Ryouta is an ordinary child with no supernatural abilities or combat training.

He cannot effectively use Gantz's weapons and depends on adults to keep him away from the mission targets.

His vulnerability becomes particularly severe because the Tanaka Aliens are fast enough to pursue participants who attempt to flee.

Ryouta enters the Tanaka Alien mission with his grandmother. Kayo initially struggles with the unfamiliar Gantz equipment but focuses on keeping him close and getting him away from danger.

As the aliens attack the scattered participants, grandmother and grandson become isolated from the more experienced hunters.

When a Tanaka Alien catches them, Kayo shields Ryouta with her own body. Both are killed in the attack, despite her attempt to protect him.

Kayo Sugimoto is Ryouta's grandmother and sole protector during the mission. Kayo Sugimoto repeatedly prioritizes his safety over her own.

Masaru Katou tries to help the inexperienced participants understand Gantz and encourages them to use the equipment available to them.

Kei Kurono participates in the same Tanaka Alien mission as Ryouta and his grandmother.