Kiyoto Takamiya is a pivotal figure in the story of Scum of the Brave, primarily known as the former master and mentor of the protagonist, Yashiro. He is an experienced professional in the brutal world of licensed bounty hunters known as "heroes," a role that carries a reputation for attracting morally questionable individuals. His reputation and expertise are such that a technique he developed, which allows a physically weaker fighter to gain an advantage over a stronger opponent in sword combat, is still taught and used by Yashiro years later.

Beneath the surface of a seasoned mentor, however, lies a much more complex and morally ambiguous individual. Kiyoto was not merely a teacher of heroes; he was also an executive of a shadowy organization called Half Dragon. In this capacity, he played an integral role in the creation of a dangerous new drug known as E4, working in conjunction with a demon lord named Lord Veil to find test subjects who could use the substance without suffering from its severe side effects, such as mutation. This secret double life places him at the center of the series' central conflicts, linking the world of legalized murder with a deeper, more insidious conspiracy.

The primary motivation driving Kiyoto's most extreme actions is a deeply personal and tragic one: the fate of his daughter, Aki Jogamine. It is revealed that Jogamine died at the age of ten during a turf war. Unable to accept her death, Kiyoto experimented on her body, using his research to resurrect her through exceptional regenerative properties. This act fundamentally shaped Jogamine's existence, granting her unusual healing abilities and potentially explaining aspects of her personality. His entire involvement with Half Dragon and the development of E4 is presented as a dark and desperate parental quest to bring his daughter back to life.

As the story progresses, the shocking truth of what Kiyoto did to his own daughter comes to light, becoming a major source of mystery and driving the plot into its next stage. This revelation forces Yashiro to reconcile the memory of his respected master with the secretive and morally compromised figure who collaborated with criminals and used his own child as a test subject. Kiyoto's legacy is therefore twofold: he is the source of Yashiro's deadly skills and the architect of Jogamine's unnatural existence, making him an absent but ever-present force whose past actions define the present struggles of the main characters. While the narrative mentions his death, the full extent of his goals and whether he truly wished to serve Half Dragon's broader ambitions remain complex questions tied to his overwhelming desire to save his daughter.