Miko Kuroda, also known by the nickname Miko, is a supporting character in Devilman Crybaby who initially appears as a fellow student at Kamigaku High School. She is a member of the running track team alongside Akira Fudo and Miki Makimura, and her athletic ability makes her the second fastest runner on the team after Miki. Miko is introduced as a quiet and reserved teenage girl with medium-length maroon hair and brown eyes, but beneath her unassuming exterior lies a deep well of insecurity, jealousy, and repressed emotions.

Her background is marked by a profound sense of inferiority toward Miki Makimura, the other girl on the track team who shares her given name. Miko feels that she is constantly living in Miki's shadow, overshadowed by Miki's athletic prowess, effortless kindness, and the admiration she receives from others. This rivalry is compounded by Miko's hidden romantic feelings for Miki, feelings she cannot openly express due to societal expectations and her own internalized shame. She resigns herself to believing she is unworthy of love or attention, and she seeks validation through unhealthy outlets, including a sexually exploitative relationship with a photographer named Nagasaki, who rapes her.

Miko's motivations are driven by a desire to be seen and valued, yet she simultaneously pushes people away. She tells another character, Myuta, to be content with admiring Miki from a distance, a reflection of the advice she gives herself: that she is not deserving of happiness or closeness. Her jealousy simmers until she is transformed into a Devilman, a change triggered by the intensity of her envy. Unlike most humans who become demons, Miko retains her human heart and consciousness after merging with a demon, allowing her to fight alongside Akira and the other Devilmen. Her transformation amplifies her repressed desires and aggression, bringing out a more violent, lascivious, and assertive side of her personality.

In the story, Miko serves as a narrative foil to Miki Makimura, representing the darker, more complex dimensions of femininity that the original manga's single Miki character embodied. Her role expands as the world descends into chaos. When human society turns against Devilmen and demon sympathizers, Miko and Miki are forced together during the escalating violence. In a pivotal moment, Miko confesses her feelings of inferiority and her love for Miki, breaking down the walls she has built. The two briefly reconcile, but the tragedy of the series continues to unfold. After Miki is brutally murdered by a human mob, Miko is captured and subjected to experimentation by humans in the final stages of the conflict. She ultimately takes her own life, committing suicide rather than continuing to endure a world that has been consumed by hatred and destruction.

Miko's key relationships center on Miki Makimura, toward whom she feels a complex mix of admiration, jealousy, and suppressed romantic love. She also interacts with Akira Fudo as a teammate and fellow Devilman, and her relationship with Nagasaki is one of exploitation and victimization, highlighting the misogyny she faces. Her development traces a trajectory from a withdrawn, insecure girl to a powerful but tormented Devilman who finally speaks her truth, only to be consumed by the apocalyptic collapse of human society. As a Devilman, she possesses enhanced physical strength, speed, and the ability to release a corrosive liquid from her transformed body, though her human will remains intact until her final moments.