Hyou

A powerful Chinese exorcist, highly skilled in geomancy, usage of seals and flying spears. He travels around China and eventually comes to Japan to seek the youkai who killed his wife and his daughter, and took out his right eye and left three long scars on his face.

[Spoiler] In his right eye socket now is a magical blue crystal ball used to save his life by his teacher. Hyou initially thinks Tora is the one who murdered his family, but Ushio convinces him Tora is innocent, and Hyou later calms down a little, becoming a valued ally. [/Spoiler]

(Source: Wikipedia)