Shuji Isaki is a contracted monk who appears in the anime Corpse Princess: Aka. He is the handler and partner to the Shikabane Hime named Minai Ruo, and his role within the story is defined by his harsh pragmatism and deep-seated personal ambitions. Unlike other monks who may show compassion for their undead partners, Isaki views Minai Ruo as nothing more than a monster and a tool to be used for his own advancement. His treatment of her is cold and brutal, reflecting a relationship with no emotional bond or mutual respect.

Isaki’s motivations are rooted in his personal history within the Kougon Sect, the organization of Buddhist monks dedicated to destroying rogue Shikabane. His older brother achieved a high level of influence within the sect by currying favor with superiors and relatives, a path of insincerity that Isaki despised. In contrast, Isaki believed in achieving status through honest means, yet he remained in his brother's shadow, fostering a deep resentment and a desperate desire to rise in rank on his own terms. This ambition drives his cruelty; he once deceived Minai Ruo into attacking his own brother by falsely claiming the sibling had become a Shikabane, an assassination attempt that ultimately failed.

Isaki’s personality is defined by his ruthless and condescending demeanor. He shows no empathy for the undead he is sworn to hunt or even the one bound to him by contract. His entire existence is fixated on the goal of obtaining a higher status as a monk, a wish that follows him even in death. This obsession proves to be his undoing, as he is ultimately cornered and killed by a group of teenagers. True to the laws of the series' universe, Isaki’s intense, unfulfilled desire to become a high-ranking monk causes him to resurrect after his death, transforming into the very thing he once hunted: a rogue Shikabane.