Kororo is a Koropokkuru (known as Minutians in the English anime) a tiny spirit people and the spirit ally of Horohoro.
Not much is known about her past. She is a Koropokkuru who helps Horohoro fight in the Shaman King tournament to reach the dream of building a vast of Butterbur.
Kororo is created by Hiroyuki Takei, and she has no information regarding any inspiration used to create her. Her Japanese voice actress is Nana Mizuki, and her English voice actress is unknown. She first appears in Shaman King volume 4 and episode 9.
NOTE: The information below is manga only info. See anime differences under "anime and manga differences" paragraph.
See Horohoro's page. She helps Horohoro create ice when Horohoro integrates her into his snowboard.
In the dub anime, her name is Corey and her race is called the Minutians.