Akoya Seishu, also known as "The Executioner," is a police inspector, the captain of the 44th Riot Squad and a secret vigilante that ruthlessly carries out his own brand of justice. He is also the affiliated fighter of Wakasa Life Insurance and represented the company during the Kengan Annihilation Tournament.

He is one of the 13 chosen fighters for the Kengan side for Kengan vs Purgatory match.

His fight against Nicolas Le Banner ended up in a Tie due to Rolón Donaire stopping the match.

After the tournament ended he thought that he isn't strong enough to enforce justice.

He also teamed up with Kiryu Setsuna and Gaoh Ryuki to eliminate Worms