Haruko is an alien being with vast knowledge of N.O. (Neurotic Overflow), a mysterious energy that allows objects to be pulled through space-time. She comes to Earth under the guise of a human and quickly inserts herself into the life of Naota Nandaba, whom she sees as a means to an end in her quest to capture Atomsk.

While claiming to work for the Galactic Space Police Brotherhood, Haruko has no real allegiance to them and instead acts independently, driven solely by her desire for power and adventure. She wields a Rickenbacker 4001 bass guitar, which she uses as both a weapon and a tool to activate N.O. portals. Throughout the series, she effortlessly switches between being a flirtatious older sister figure, a rebellious anti-hero, and a ruthless manipulator.

Haruko’s presence in Mabase throws Naota’s life into turmoil, forcing him to confront emotions and situations he is not prepared for. Though she often acts as if she cares for him, it becomes clear that she sees him as little more than a pawn in her larger game. Despite this, she does display moments of genuine affection or amusement toward him, hinting at a more complex personality beneath her erratic behavior.

Haruko has short, peach-colored hair with bangs that frame her face and bright yellow eyes. She is almost always seen wearing a red jacket with a white scarf, fingerless gloves, and knee-high boots. She rides a yellow Vespa scooter, which is as much a part of her identity as her bass guitar. Her expressions and movements are exaggerated and cartoonish, matching her wild and unpredictable personality.

Haruko is loud, energetic, and completely unpredictable. She operates on pure impulse, acting according to her whims with little regard for the consequences. She has a sharp tongue and a mischievous streak, often teasing or manipulating others for her own amusement. Her antics make her seem fun and exciting, but beneath her carefree facade, she is highly cunning and self-serving.

She has an almost childlike fascination with power and adventure, but her single-minded pursuit of Atomsk blinds her to the feelings and well-being of those around her. While she occasionally shows moments of care or sentimentality, she never lets them interfere with her goals, making her a dangerous and morally ambiguous character. Despite her manipulative nature, Haruko’s boundless energy and rebellious spirit make her one of the most charismatic characters in FLCL. She embodies the themes of chaos, desire, and unattainable dreams that permeate the series.

• Arrival in Mabase
  Haruko crashes into Naota’s life literally by hitting him with her Vespa and then striking him on the forehead with her bass guitar. This seemingly random encounter activates Naota’s N.O. abilities, allowing robots and other entities to emerge from his head. She then moves into his house under the pretense of being a live-in maid, though her true intention is to use him as a conduit to reach Atomsk.

• Manipulating Naota
  Throughout FLCL, Haruko plays with Naota’s emotions, acting as an older sister, a love interest, and a tormentor all at once. She flirts with him, encourages his rebellious streak, and pushes him into increasingly dangerous situations, all while pretending to care about his development. In reality, she is testing and using him, seeing how much of Atomsk’s power she can extract through him. She also has a complex relationship with Commander Amarao, an agent of the Galactic Space Police Brotherhood who is aware of her true nature. Their interactions suggest a history of betrayal, with Amarao warning Naota that Haruko will discard him once he is no longer useful.

• Final Confrontation
  As the series reaches its climax, Haruko’s schemes come to a head when Atomsk is finally summoned. Rather than capturing him, however, she is once again outmatched and left empty-handed. Naota, having grown through his experiences, refuses to let her control him any longer. In a moment of defiance, he embraces his own power and makes his own choice, signaling his maturity and growth. Haruko, despite her failure, takes it in stride, leaving Earth in pursuit of her next scheme.