Takamasa Sougi serves as the Gon Sojo for the Ikai and Yanatsu districts under the Kougon Sect, promoted after Shuji Isaki's death to oversee anti-Shikabane operations. He partners with the Shikabane Hime Itsuki Yamagami, whom he contracted after an unexpected encounter while she was his student. Initially unfamiliar with Shikabane Hime or contracted monks, Takamasa struck Itsuki as clumsy. Their partnership later fostered mutual romantic feelings, though neither acts upon them due to Itsuki's undead state. In combat, he wields a Japanese daikyū yumi bow, utilizing specialized Zadan magic to support Itsuki against rogue Shikabane.

A tragic event shapes his past: his childhood friend Tomoharu Kishibe died in a reckless driving accident, transforming into a Shikabane. Four years later, Takamasa and Itsuki confronted and eliminated Tomoharu to end his suffering. This profoundly impacts Takamasa, fostering a reserved, duty-bound personality and a wariness of emotional bonds with the undead, contrasting Ouri Kagami's approach. For his duties, he once operated undercover as a nurse and sports teacher at Ouri's high school to monitor the traitor monk Akasha Shishidou, wearing a white lab coat and demonstrating archery skills that intrigued students.

Stoic and conscientious, Takamasa treats Itsuki with notable respect compared to other monks. While his trauma contributes to a serious outlook, he maintains diverse interests beyond monastic duties. Additional details include his blood type (O), partial visual impairment (40% eyesight in both eyes), preference for fried eggs and dried mackerel, aversion to time-consuming tasks, height of 172 cm, and weight of 60 kg.