Jyuuzou is a central figure in the story, a man whose life is defined by sharp contradictions between his public success and private turmoil. He is the founder of the renowned Sugaya merchant house in Nihonbashi, a prominent establishment he built from nothing through tireless effort and remarkable business acumen. Even into his fifties, he continued to work with unwavering dedication to his trade, presenting a face of a sincere, dedicated, and strict merchant to the world.

Beneath this veneer of success, Jyuuzou's personal life was fraught with conflict and tragedy. His heart was deeply conflicted when it came to his own family. He harbored a brutal and open disdain for his daughter, Suzune, who was born from a tragic act of violence against his wife. In stark contrast, he showed deep, unwavering affection for an orphan named Natsu, whom he raised with genuine love. This complicated family dynamic extended to his biological son, Jinta. The two were eventually reunited, but they never developed a true parent-child bond, with their relationship remaining distant even as Jyuuzou showed occasional slivers of recognition toward him.

This internal conflict and the weight of his past ultimately sealed his fate. Jyuuzou became a habitual drinker of a cursed sake known as Yukinagori. This substance set him on a dark and irreversible path, leading to his physical and spiritual transformation into a demon-like creature. In a final, tragic turn, his descent concludes with his death at the hands of his son, Jinta, who is forced to slay him after he has become a demon. No information is available about notable abilities beyond the transformative and destructive effect of the cursed sake.