Ruuko Kireinasora

An enigmatic girl who claims to be an alien from the third planet "ruu" in the constellation Ursa Major 47 and calls herself "Ruuko Kireina Sora." After a strange encounter with Takaaki, she transfers to Takaaki's class as a foreign exchange student. Her personality is self-indulgent and elusive. She speaks in a unique "ruu" language.

Spoiler

According to the ending of ToHeart2, she is from California, USA. Her father is a lawyer, her mother is a conservationist, and her real name is Lucy Maria Misora.