Takamasa Sogi operates as a Contracted Monk for the Kōgon Sect, bound to the Shikabane Hime Itsuki Yamagami. Their partnership embodies a deep mutual commitment, forging a Battle Couple who fight side-by-side against Shikabane. Takamasa wields a bow and arrow with calm precision, embodying the Aloof Archer archetype.

He is the son of Genpaku, a renowned monk within the sect. Itsuki specifically chose Takamasa, believing his inherited strength would hasten her mission to defeat Shikabane and achieve ascension. Romantic feelings complicate their duty, made impossible by Itsuki's undead state—a painful limitation marked by the scars on Takamasa's chest from past attempts to bridge that divide.

A critical failure defines him: his hesitation to kill a close friend turned Shikabane led to multiple deaths, forging his reserved and stoic personality and reinforcing his strict adherence to sect protocols on emotional detachment. Yet, he and Itsuki persistently test these boundaries through fierce loyalty and concern.

Following Keisei Tagami's death, Takamasa mentors Ouri Kagami, training him to become Makina Hoshimura's new Contracted Monk. He explicitly cautions Ouri against the dangers and futility of romance with a Shikabane Hime, drawing on his own anguish with Itsuki. Paradoxically, his guidance hints at an unspoken hope that Ouri might transcend the limitations that confined his own relationship.

Takamasa remains actively engaged in the sect's critical missions, confronting rogue Shikabane and internal threats like the traitor monk Akasha Shishido. He deploys his tactical expertise and combat skills coordinating defenses and safeguarding sect interests.