Oalian is like no other creature on the surface of Eberron. Some stories claim that they were once a tree, awakened by the original Gatekeepers to serve as a living repository of their traditions. Other stories claim that Oalian was the first tree, and is as old as the world. If Oalian knows the truth of their origin, they have never chosen to share it.
This ancient tree gained sentience before humans even set foot upon Khorvaire's shores. Wise beyond comprehension, they serve as the leader of the Wardens of the Wood and the Eldeen Reaches, though all druidic sects pay them some heed. Their knowledge is not limited to the past, and they have been known to dispense prophetic wisdom when it is deemed necessary.
With the loss of so many elders in the Last War, Oalian's influence has waned a bit. Some members of the younger generations seek to take matters into their own hands rather than listen to a stuffy old tree.