Hideyuki Makimura is a former police detective whose life and death serve as a foundational element within the narrative of Angel Heart. He is the original City Hunter, a vigilante who operates in the Shinjuku district, taking on cases to clean up the streets before he ever partners with Ryo Saeba. Unlike his partner, Hideyuki is calm, composed, and methodical, presenting a deadpan demeanor that contrasts sharply with the more flamboyant nature of his future partner. He is a responsible and neat individual, capable of handling household chores and is deeply protective of his family, especially his foster sister, Kaori Makimura.

Hideyuki's motivations are rooted in a strong sense of justice, a trait that drove him during his time at the Tokyo Metropolitan Police Department where he was a colleague of Saeko Nogami. He eventually resigned from the police force following an incident that left him feeling responsible, choosing instead to become a sweeper who deals with criminals that escape the law. In the world of Angel Heart, his role is uniquely established as the founder of the City Hunter operation, with Ryo Saeba later joining him as a partner after a fateful encounter. Before his death, Hideyuki was responsible for gathering information, confirming client assignments, and acting as the strategic backbone of the team.

His key relationships define much of his character. He is the best friend and original partner of Ryo Saeba, a bond formed when Ryo was sent to kill him but instead chose to abandon his mission after meeting Kaori. Hideyuki saw the potential in Ryo and offered him a new path, a decision that would lead to a deep and lasting partnership. With his foster sister Kaori, Hideyuki shares a profound, non-blood-related familial bond, having raised her as his own sibling after their father brought her home. He had planned to reveal the truth about her origins on her twentieth birthday but was murdered before he could do so, leaving his dying wish for Ryo to take care of her. Furthermore, Hideyuki shares a deep history with Saeko Nogami, with their relationship being so significant that he had even seriously considered marrying her before his untimely death.

Throughout the series, Hideyuki's development is explored through flashbacks that reveal his past and the origin of City Hunter. It is shown that he was the one who originally hired Ryo, and that he and Kaori gave Ryo his name. His death is a pivotal event that shapes the lives of the remaining characters, creating a lasting emotional wound for both Ryo and Saeko. In terms of abilities, Hideyuki is a skilled operative, but his talents lie more in information gathering and strategic planning than in direct, dirty fights. He is proficient with firearms, known to favor a Colt Roman MK III and a Smith & Wesson-style double-action revolver. His car of choice is a first-generation Mazda Carol. Ultimately, Hideyuki Makimura is remembered as a just and caring individual whose legacy as the original City Hunter and as a brother continues to drive the story forward.