Ittō Hagane, formerly known as Shuhei, serves as a Tetra Sealer for the antagonistic Noroi Faction. His childhood was marked by severe trauma when he witnessed his parents sell his sister into slavery, leaving deep emotional scars. Later, while training in swordsmanship, his master betrayed him, attempting murder out of fear that Hagane's growing skill would eclipse his own. These betrayals fueled Hagane's resentment towards humanity, making him receptive to the Noroi Faction's promise of power and purpose through service to the dark entity Noroi.

As a high-ranking enforcer within the faction, Hagane confronts the protagonists—Takamaru Ikusabe and the Blades, including Haruka Takamori—during their missions to stop Noroi's resurrection. He possesses the distinctive physical trait of perpetually closed eyes. His fighting style and motivations are deeply rooted in his tragic past, driving his commitment to Noroi's cause of spreading despair and corruption.

A critical narrative revelation exposes that Haruka Takamori, one of the primary Blades, is Hagane's long-lost sister. Originally named Haru, she was separated from him after being sold into slavery. This shocking discovery creates a profound personal conflict for Hagane, challenging his allegiance to the Noroi Faction and his worldview, forcing him to confront his past actions and the ideological divide between them.

Hagane's character arc culminates variably based on player choices and narrative routes. In some paths, he achieves redemption, abandoning the Noroi Faction upon recognizing the possibility of reconciliation and familial bonds. Alternatively, other routes depict his continued descent into darkness, where he fully embraces Noroi's nihilistic goals. His ultimate fate remains variable, reflecting the story's branching outcomes.