Kakuma

One of the two survivors of the Hima clan. She is one of the twins of the former leader whose entire clan was killed by Reishin and Hiyou in their attempt to destroy the Tera Stone. In the manga, Kakuma's contractee is Keita's grandfather Nagamine Ryuujin. Kakuma sacrifices her life and turns into the tera stone after the original tera stone was destroyed by Hiyou. Kakuma's Exceed is Shining Gallop which takes the form of a white galloping horse. In the anime however, she was sacrificed in order to annihilate the barrier and open the path to the Pure land, the island holding the Terra stone.

(Source: Wikipedia)