Yu Di is the protector spirit of Tao,a Taoist Priest who seals and destroy bad spirits.
Yu Di,in life was a great warrior at Shang house,but he died in the great War of Eight Living Spirits(A war started by former Taoists,know as Necromancers)
After 500 years his spirit still defend the fortress who his master give him in care,scaring people to stay away.Tao go there to seal him to be sent in spirit world,but that its just the begining...
www.planetminecraft.com/skin/yu-di/