The White Hermit and Black Hermit act as Kyogoku Tei's messengers, delivering his orders to the supernatural Ongyou trio. They always appear together as a pair. While their natural forms resemble elderly women, they strategically adopt the deceptive guise of young girls to manipulate others and further their master's schemes.

Their actions display unwavering devotion to Kyogoku Tei, lacking any personal motives beyond executing his will. Their singular focus is advancing his plan to blanket the world in darkness using the Flame Lance cannon. This includes recruiting others into his service, such as intercepting the Ongyou's judgment of Tatsuta to bring her under Kyogoku Tei's command. Tatsuta subsequently participated in the Seven Man Point massacre orchestrated by him.

Their existence ends during Kyogoku Tei's final defeat by the Ongyou. Consumed by the collective darkness of his victims, he accidentally unleashes destruction. The Hermits perish alongside him, caught in the resulting inferno. No background, origin, or personal development for the White Hermit and Black Hermit is documented; they remain extensions of Kyogoku Tei's will.