Director Sawa is the director of the hospital where the protagonist Ray works, a figure who combines a frightening exterior with a deeply caring nature. He is instantly recognizable by the eyepatch he wears, a physical mark of the cost of his past heroism. Years before the main events of the story, Sawa rescued Ray when she was a child left for dead after being exploited by an illegal organ-harvesting syndicate. During this rescue, he lost his right eye and his leg, and he now uses a prosthetic or a peg leg. Despite these profound injuries, he remains a formidable presence, demonstrating that his physical disabilities have not diminished his capabilities.

Sawa's personality is defined by a sharp contrast between his demeanor and his true intentions. He enjoys presenting himself as a frightening, authoritarian figure, often using intimidation as a tool, particularly during his first encounters with others. However, this intimidating facade conceals a genuine and profound care for both his patients and his staff. He is not merely an administrator but a protector and a father figure, especially to Ray, whose life he saved and whose development as a doctor he oversees. This protective instinct extends to the hospital as a whole; he commands a team of nurses who, like him, are capable of significant action when threats arise.

In the story, Sawa serves as a foundational pillar for the hospital and a guardian of its staff. His most critical role is as the man who gave Ray a second chance at life, offering her safety and a purpose after her traumatic childhood. His past is deeply intertwined with the central mysteries of the series, as he once worked alongside Dr. Kasugano, who is Ray's biological mother, and the antagonist known as the H Ring Man. Their collaboration ended in a schism approximately twenty years before the narrative begins, placing Sawa in a position of deep, personal knowledge about the syndicate Ray is trying to unravel. While he holds crucial information, he is reticent to share it, believing that protecting Ray from the dangerous truths of her past is more important than satisfying her quest for answers.

Key relationships define Sawa's position in the world of Ray. His bond with Ray is the most significant; he is her savior, employer, and a stern but caring guardian. Their relationship is complex, as Ray sometimes accuses him of toying with lives, but the underlying current is one of deep, if unspoken, gratitude and respect. His history with the H Ring man and Dr. Kasugano places him in a unique position as a former ally turned opponent of the primary antagonist, giving him a perspective on the conflict that few others possess. Furthermore, his relationship with the hospital staff is one of leadership and loyalty; they are not just employees but a dedicated team capable of rising to any challenge under his direction.

In terms of development, Sawa is a character whose backstory has already shaped him. The significant development occurred in his past when he made the choice to save a child and lost his eye and leg in the process, solidifying his resolve and his method of operating. Throughout the series, his unwavering nature serves as a constant, a rock from which other characters can confront their own crises. His most notable abilities are a unique blend of medical directorship and exceptional physical combat skills. Despite his missing leg, he is a highly capable martial artist. Notably, he uses his peg leg as a pivoting point to execute a particularly powerful Hurricane Kick, demonstrating that he has transformed a disability into an advantage in combat. This duality, being both a top medical authority and a physical powerhouse, makes him an embodiment of the series' more extraordinary elements, a ninja-like doctor whose actions speak as loudly as his intimidating presence.