Yamakatsu Katsuya

Yamakatsu was Ganta and Mimi's school friend. He was killed during the Nagano school massacre by the Red Man. He was always seen with a soccer ball.

Yamakatsu's last name is Katsuya, but this was only mentioned by Mimi's father (an anime-only character), so it's not canon.

Yamakatsu is voice by Shohei Kajikawa in Japanese and by Micah Solusod in English.