Celestial Hybrid.

A Celestial Hybrid is like most Celestials in a lot of ways. They have Authority and need faith to create divine energy and advance their domains except that Celestial Hybrids have a unique divine energy. The tree father has the divine life energy that is strong enough to resurrect a mortal and create transcendents from ordinary trees. 

The tree father can also spread its seeds as a life tree does. The original life tree was the body of the high elf ancestor. The other avatars are from its seeds. The seeds of the tree father grow into his avatar instead of new life trees because Life trees can create seeds and gods can have avatars. The fusion of these two abilities brought about the avatars.