Kayo Sugimoto

Kayo is kind, nurturing and deeply devoted to her grandson. Her first concern throughout the Gantz ordeal is Ryota's comfort and safety rather than her own chances of surviving.

She is frightened and understandably dependent on others for direction. Unlike hunters who quickly begin experimenting with weapons, Kayo follows instructions and hopes that someone more capable understands how to escape the situation.

Her maternal instincts become stronger when danger approaches. Even when she has little ability to fight effectively herself, her immediate response is to put herself between Ryota and whatever threatens him.

Kayo has no supernatural abilities or combat training. At seventy-four, she is physically less capable than most participants selected by Gantz.

Masaru Katou persuades her and Ryota to wear the Gantz suits, giving them access to the same enhanced protection available to other hunters.

Kayo nevertheless demonstrates no significant proficiency with Gantz weapons. Her role in the mission remains focused on protecting and comforting Ryota rather than hunting aliens.

Kayo and Ryota appear among the new participants assembled for the Tanaka Alien mission. Their presence shocks the younger hunters because neither appears remotely suited to the lethal task Gantz has assigned them.

They initially remain with Katou's group but eventually become separated from the better-protected hunters. When Tanaka Aliens corner them, Kayo attempts to shield Ryota with her own body. Both grandmother and grandson are killed in the attack.

Their experience reinforces the arbitrary brutality of Gantz: participants are not selected because they are capable soldiers, and innocent people can be placed into missions they have almost no realistic preparation to survive.

Ryota Sugimoto is Kayo's grandson and the person she cares about above everyone else. She comforts and protects Ryota Sugimoto throughout their time in Gantz.

Masaru Katou becomes the participant Kayo trusts to guide them through the unfamiliar situation. He convinces her and Ryota to use the protective suits and attempts to keep the inexperienced pair with his group.