Dr. Arisugawa, a pioneering scientist specializing in digital networks and virtual reality, created groundbreaking inventions including the World Link, the Dive System, and the Magical Gate cyber park. This virtual playground allows children's consciousnesses to upload via global computer networks. To protect it, he developed autonomous defensive programs called Web Knights, designed as guardian entities specifically for safeguarding the Magical Gate and its young users.

He shares a familial connection to the series' events through his granddaughter, Aoi Arisugawa, who actively engages in missions involving the Magical Gate. Its management system is governed by an artificial intelligence named Ange, whose personality mirrors his late daughter-in-law, Mika Arisugawa. Ange’s appearance shifts based on the observer, though she typically manifests as a fairy-like entity with wings.

Physically, Arisugawa appears as a senior individual with gray hair extending to his ears and gray eyes. His technological legacy becomes pivotal when the Magical Gate is compromised by the mysterious Deletloss computer virus. This corruption subverts the Web Knights, turning them against the children they were meant to protect. The ensuing crisis requires intervention by human protagonists and the sole uncorrupted Web Knight, Gladion.