Gantz character. A friend of main character Kurono Kei and the one who gets him in this mess in the first place. He and Kurono have opposite strengths and weaknesses; in Katou's case, heroism comes easily to him, but courage and determination don't.
Katou is one of the most important Gantz team members, even spending some time as the leader. He's also the oblivious target of Kishimoto Kei's love, and later Yamasaki Anzu's.