Haruka Tenou, known as Sailor Uranus, is introduced in the third season of the anime as a new type of guardian, one who operates in the shadows with a more pragmatic and morally complex viewpoint than the series' main heroines. As a civilian, Haruka is a tall, athletic sixteen-year-old with short, windswept blonde hair and a confident, often androgynous appearance. She attends Mugen Gakuen, an elite academy, but wears the male uniform, a choice that leads her new acquaintances, including Usagi Tsukino and Minako Aino, to initially mistake her for a handsome boy.

Haruka's personality is defined by her fierce independence and a hardened resolve born from her self-appointed mission. She is bold, outspoken, and possesses a strong, sometimes brash, will. Unlike the Inner Sailor Guardians who prioritize saving everyone, Haruka is an unwavering pragmatist, famously declaring a willingness to sacrifice innocent lives if it means preventing the destruction of the world. This can make her seem cold or callous, especially to the idealistic Sailor Moon, with whom she initially clashes. Despite this tough exterior, Haruka is deeply protective of those she loves, particularly her partner Michiru, and has a playful, teasing side, often flirting with other girls as a casual game.

Her primary motivation is the completion of her mission alongside Michiru Kaiou, Sailor Neptune. Together, they are searching for three special items known as Talismans, which are needed to summon the powerful Sailor Saturn and avert the coming of Silence, an apocalypse-level event. Her role in Sailor Moon S is that of an antihero; she and Michiru operate independently of Sailor Moon’s team, believing their greater experience and willingness to make hard choices make them better suited to handle the threat of the Death Busters. Her backstory reveals that she initially rejected her destiny as a Sailor Guardian, loving her life as a normal human too much to risk it, until an attack that injured Michiru forced her to accept her transformation and her duty.

The most significant relationship in Haruka's life is with Michiru Kaiou. They are partners in every sense, both as Sailor Guardians and as a romantic couple, living together and presenting a united front in all things. Haruka takes on the more dominant, protective role in their dynamic. Initially, she treats the Inner Guardians, especially Sailor Moon, with suspicion and distance, dismissing them as unprepared for the gravity of the threat. However, through shared battles and mutual respect, she eventually comes to acknowledge Sailor Moon's strength of heart. Her relationship with the other Outer Guardians, Setsuna Meiou (Sailor Pluto) and the reborn Hotaru Tomoe (Sailor Saturn), is that of a close ally and, in Hotaru's case, a parental figure, with the child affectionately calling Haruka "Papa".

Over the course of the season, Haruka undergoes subtle but important development. She begins as a solitary, secretive figure who sees her mission as a grim necessity beyond the understanding of the younger guardians. Through her forced cooperation with Sailor Moon, she learns to trust in a different kind of strength—one rooted in compassion and the belief that no one should be sacrificed. Her unwavering devotion to Michiru remains her constant, revealing that her cold pragmatism is balanced by a deep, personal love that she is unwilling to sacrifice, even for the sake of her mission.

As Sailor Uranus, her powers are associated with the sky, wind, and earth. She is a physically imposing fighter, relying on speed and raw strength. Her notable abilities include the attack World Shaking, which channels tremendous force, and later, the Space Sword Blaster. She is the bearer of the Space Sword, one of the three Talismans, which she wields as her primary weapon. Even in her civilian form, Haruka is a world-class race car driver and excels in athletics like track and field, reflecting her love for speed and competition. She also possesses a hidden talent for playing the piano.