Mima Kirigoe is the protagonist of the psychological thriller film Perfect Blue. She begins her journey as a member of the J-pop idol group CHAM!, where she cultivates a public persona of a wholesome, bubbly, and innocent young woman adored by fans. However, Mima privately feels suffocated by this manufactured image and decides to leave the group to pursue a career as a serious actress, seeking greater authenticity and personal autonomy.

Her background as a pop idol shapes her initial personality. She is sweet, polite, and eager to please, often displaying a timid and uncertain nature as she navigates the unfamiliar world of acting. She is ambitious and determined to prove herself in her new profession, but she is also deeply introspective and vulnerable, wrestling with the expectations imposed by her fans and the entertainment industry.

Mima's primary motivation is to shed her pure pop idol image and establish herself as a respected actress. This desire for professional evolution and self-determination drives all of her major decisions, including her willingness to accept controversial and mature roles. This ambition, however, places her in direct conflict with the obsessive elements of her fanbase and her own internalized former persona.

At the start of the story, Mima is a passive and somewhat indecisive young woman trying to manage a risky career change. As she becomes the target of an obsessive stalker and faces exploitation within the acting industry, her psychological state begins to deteriorate. The pressure from filming a traumatic rape scene for the crime drama Double Bind, combined with the relentless stalking and the discovery of a fake online diary called Mima's Room that details her every move, causes her to become increasingly paranoid, isolated, and unable to distinguish reality from hallucination. She is haunted by an apparition of her former idol self, which taunts and destabilizes her. Her personality fragments as she descends into a state of psychosis, doubting her own memories and actions.

Mima's key relationships are central to her development. Rumi Hidaka, her manager and a former pop idol herself, initially appears protective but is later revealed to be the true antagonist. Rumi, unable to accept Mima's departure from idol life, develops a dissociative identity, believing she is the real Mima. She orchestrates a campaign of gaslighting and murder to destroy Mima's new identity. The stalker known as Me-Mania represents the toxic side of fandom; he worships Mima's idol persona and feels betrayed by her career change, making him a dangerous pawn in Rumi's scheme. Her agent, Tadokoro, pushes her into more exploitative roles for the sake of her career, while her former bandmates in CHAM! represent the past she is trying to leave behind.

Through the intense psychological and physical trauma she endures, Mima undergoes a profound transformation. She is forced to confront her tormentor and the fractured parts of her own identity. After surviving the final confrontation with Rumi, who is institutionalized while still lost in her delusion, Mima emerges changed but more resilient. She has integrated her experiences and asserted control over her own life. The film concludes with Mima, now an established actress, confidently declaring her own reality after overhearing strangers doubt her identity.

Mima does not possess supernatural abilities. Her notable abilities are her artistic talents as a singer and an actress. Her versatility and adaptability as a performer allow her to take on challenging roles, but her psychological resilience is her most significant trait. Her journey from a fragile, uncertain idol to a woman capable of surviving extreme trauma and reclaiming her sense of self is the core of her character.