Sensei commands the supernatural crime syndicate and cult Palm of the Hand RS, profiting from illicit activities like necromancy and curse placements. The organization exploits spiritually vulnerable individuals, such as Erika Hiura, as mercenary necromancers.

Sensei inherited the group's legacy from its founder, Hiyakawa Rihito's mother. After her involvement, Sensei assumed leadership, expanded operations, and maintains control through spiritual manipulation and parasitic entities. These supernatural parasites are embedded within followers to enforce compliance and loyalty, a predatory method targeting those with spiritual sensitivity or traumatic pasts.

Sensei's influence drives the series' central conflict, particularly concerning Erika Hiura and Hiyakawa. Erika initially serves as a curse mercenary under Sensei's direction, while Hiyakawa's personal connection stems from his mother's past involvement. Sensei's operations catalyze confrontations between the Palm of the Hand RS and protagonists working to dismantle the organization.

Symbolizing a cycle of spiritual abuse and exploitation, Sensei represents the corrupting force characters like Hiyakawa and Erika must overcome to resolve their traumatic histories.