Isato is a 17-year-old apprentice monk serving as the Suzaku of Heaven, one of the Eight Guardians destined to protect the Priestess of the White Dragon. He stands 172 cm tall, with a birthday on July 31 and blood type O. His commoner parents and two unnamed elder brothers, established monks, previously served the Taira clan as housekeepers. His mother breastfed both her children and Katsuzane Taira, making Isato and Katsuzane foster brothers raised together in the capital's slums. Though childhood playmates with other slum children, their bond later strained. A catastrophic fire in the capital when Isato was nine proved pivotal. Separated from friends, he actively searched for survivors and guided samurai to Katsuzane's location. Despite his efforts, he failed to save many friends and relatives, leaving him traumatized. Disillusioned, his parents withdrew from Taira service and returned to the slums. Isato joined his brothers as a temple apprentice, where he occasionally spotted Katsuzane but avoided contact. This experience fostered initial distrust and prejudice against the nobility. As an apprentice, he performs duties like maintaining temple grounds, chanting mantras, meditating, patrolling for alms, and receiving basic martial arts training for self-defense. Politically neutral yet leaning toward the Retired Emperor's faction, his personality blends energetic kindness, protectiveness toward children, and a habit of biting his thumbnail when nervous, alongside a volatile temper triggered by perceived injustice. He favors the scent of kayou, the color light red, hardy begonias in autumn, and Christmas camellias in winter, often frequenting Gion Temple, Hinomiko Shrine, and Nono Temple. He extends skepticism to Karin, the newly arrived Priestess of the White Dragon, as another Priestess, Chitose, is already recognized by the Retired Emperor. While rescuing Karin from nobles, he doubts her authenticity, especially after she falls victim to a vengeful spirit's curse. Over time, he admires her determination and resolves to protect her regardless of legitimacy. His interactions with Akifumi (Suzaku of Earth and crown prince) shift from hostility to tentative trust after Akifumi risks his life to save him during an earthquake conjured by Shirin. In the Emperor's story route, he initially believes Karin can magically resolve the capital's strife but later accepts her power's limitations, tempering his anger toward nobles under her guidance. Personal romantic routes shape his development differently. In the Retired Emperor's route, Heart Pieces help him rediscover fire memories, confessing despair over noble indifference and inevitable death. Karin's rebuttal—emphasizing finding joy through living fully—reshapes his outlook, leading him to confess his feelings and plead for her to stay. In the Emperor's route, he grapples with helplessness after realizing Karin cannot instantly fix societal issues; her compassion helps him manage his anger and adopt a more hopeful perspective. In the crossover title *Yume no Ukihashi*, Isato is among the guardians abducted into a dream world. He collaborates with Eisen to break seals using mantras and may appear as a starting guardian or prisoner. His romance routes involve collecting "Little Dream Boxes" to unlock events strengthening his bond with Karin, culminating in potential romantic or farewell endings based on player choices.