Kororo is the spirit ally of Horohoro (Usui Horokeu), a Koropokkoru—basically tiny fairy-like beings from Ainu mythology whose name literally means "little people under butterbur leaves." She goes by Corey in the English anime, where her species is called Minutians instead.
Despite being a spirit rather than human, Kororo has developed a pretty obvious crush on Manta Oyamada throughout the series. Her English name is a play on "Kouri," the Japanese word for ice, which fits perfectly since Horohoro's whole fighting style revolves around ice-based attacks. She's generally portrayed as cute and earnest, serving as both Horohoro's companion and comic relief.
Content compiled by AnimeList.moe from publicly available sources.
