The character known as Detective, more precisely named Hideyuki Makimura, serves as a foundational figure in the City Hunter narrative, appearing at the very beginning of the story. His primary role is that of the original partner and best friend of the protagonist, Ryo Saeba, and together they form the team known as City Hunter. Before this partnership, Hideyuki was a detective with the Tokyo Metropolitan Police Department, a position where he was a colleague of the determined police officer Saeko Nogami. His strong sense of justice was evident during his time on the force, but he eventually resigned to work alongside Ryo.

In terms of personality, Hideyuki is portrayed as a calm and neat individual, the complete opposite of his partner Ryo. While Ryo is reckless and lecherous, Hideyuki is responsible, capable of handling household chores, and dedicated to his work. He is also deeply protective of his family, particularly his foster sister, Kaori Makimura. His appearance is marked by severe myopia, requiring him to wear thick glasses. His motivations are rooted in a desire for justice and a sense of duty, which drives him to take on the dangerous work of a sweeper or private detective cleaning up the city's crime.

Within the story, Hideyuki plays a crucial role as the operational backbone of City Hunter. Beyond simply being a partner, his job involves confirming assignments and gathering vital information, a function that highlights his methodical and responsible nature. The tragedy of his death is the primary catalyst for the entire series. He is murdered by a powerful criminal syndicate, the Union Teope in the manga or the Red Pegasus drug organization in the anime. His dying request to Ryo is to take care of his sister, Kaori. This event not only drives Ryo’s quest for revenge but also brings Kaori into the role of Ryo's new partner, establishing the core dynamic of the series. His death is a defining moment that hangs over the characters throughout their subsequent adventures.

Key relationships define his character. His bond with Ryo Saeba is that of a trusted best friend and partner, built on mutual respect despite their contrasting personalities. His relationship with his foster sister, Kaori Makimura, is one of deep, protective care. He harbors a secret that he intends to reveal to her on her twentieth birthday—that they are not actually blood-related—but he is killed before he can do so. He also maintains a professional relationship with his former police colleague, Saeko Nogami, who continues to work with the City Hunter team even after his death.

Regarding development, Hideyuki’s narrative arc is tragically cut short, but his influence leads to the development of other characters, especially Ryo and Kaori. His death forces Ryo to confront loss and take on a protective, quasi-familial role he never asked for, while Kaori must step into her brother's dangerous world to honor his memory and stay close to Ryo. In terms of notable abilities, as a former detective and a partner to Ryo, Hideyuki is skilled in investigation and information gathering. He is also proficient with firearms, favoring a Colt Roman MK III revolver, and in the anime, he is shown driving a yellow Volkswagen.