Lucy Maria Misora, also known as Ruuko Kireinasora, presents herself as a mysterious transfer student from the planet Ru, identified as the third planet in the constellation Ursa Major 47. She adopts the Earth name Ruuko Kireinasora, meaning "beautiful sky," upon joining Takaaki Kouno's class. Her appearance is marked by long, straight lavender hair reaching her waist and distinctive crimson eyes with a subtle purple hue. She consistently wears a long-sleeved pink sailor-style school uniform featuring a white-lined red collar with a double neckerchief-like ribbon, red cuffs, a red miniskirt with white linings, black socks, and brown shoes. Initially, her communication is unintelligible, described as "starfish language," until she adjusts a translation device by tapping her head. She exhibits unique verbal patterns, frequently raising her arms while uttering "rū" as a greeting and referring to humans as "ū." She demonstrates the ability to commune with animals, notably forming a bond with a stray cat she names "the Nya," a species she finds unique for its capacity to enjoy food. In one incident, she summons a thunderbolt to split a tree, creating a bridge to rescue this cat from a river with Takaaki's assistance. Her background involves using matchsticks as currency from her home planet, valuing them highly enough to purchase items like a rocket engine on Ru. On Earth, she attempts transactions with matchsticks, such as buying meals in the school cafeteria or acquiring a charcoal clay pot for cooking fish for the Nya. She writes using Egyptian hieroglyphs. Cultural differences surface in her statement that on Ru, "the only good Uu is a dead Uu," though she makes an exception for Takaaki, deeming him a "special Uu." She is generally expressionless, self-indulgent, and elusive, maintaining limited social connections and often appearing solitary. Her preferred culinary method on Earth is broiling fish over charcoal in a clay pot. In expanded narratives like the AWA fics, she attends the AWA Academy as a student. Her fictional birthdate is noted as February 30th. Across various adaptations—including the original series, OVAs like *To Heart 2 AD*, *AD Plus*, and *AD Next*, and games such as *To Heart 2 AnotherDays* and *Final Dragon Chronicle: Guilty Requiem*—her core traits of alien identity, communication quirks, and animal kinship remain consistent without significant evolution in her character arc.