Kiyoshi Murata is a complex figure within the narrative of MPD Psycho, existing both as a distinct personality within a multiple system and as an individual with his own separate history. The character is introduced as one of the alternate identities residing within the body of a former detective. Within this system, Murata is distinctly characterized as a corrupt police officer who leaks information to criminals, a role that places him in moral opposition to the other personalities, such as the serious criminologist Kazuhiko Amamiya.

The narrative reveals that the body's original personality is not Murata but rather a psychopathic individual named Shinji Nishizono. The personalities of Yosuke Kobayashi (the detective) and Kazuhiko Amamiya originated as childhood friends of Nishizono who were victimized by him. The true, original Kiyoshi Murata was a separate person who played a significant role in this traumatic past, described as somewhat shy and mentally disabled. In a flashback, this original Murata assists the young Shinji Nishizono in disposing of the corpses of other children and a nurse. He refers to Shinji affectionately as Shin-chan and mentions that Shinji was the only one who did not bully him, indicating a relationship of loyalty born from a desperate social dynamic. This original Murata meets a grim end, being burnt to death after a fire ignites oil that had been poured on him.

In the present timeline, Kiyoshi Murata functions as one of the fragmented personalities within the host body. His motivations are less about solving crimes and more aligned with survival and a cynical self-interest, contrasting sharply with the investigative drive of the Amamiya personality. The interactions between these identities are a central element of the story, as the personalities are not fully aware of each other's thoughts or actions. Amamiya lacks access to Murata's knowledge, and neither is fully aware of the brutal inclinations of Shinji Nishizono. This lack of internal communication forces the reader to piece together the central mystery alongside the characters, as Murata may hold crucial pieces of the puzzle that the dominant personality cannot access.

Kiyoshi Murata is also defined by his unique mannerisms. In translated versions of the manga, his speech pattern is notably slow and drawn out, which differentiates him from the other personalities and can affect the reading experience, creating a distinct rhythm for his dialogue. His role is pivotal to understanding the full scope of the plot, as he embodies the fragmented and unreliable nature of the protagonist's memory, holding secrets that are vital to unraveling the complex web of past and present crimes.