Who is Watch-wher from Dragonflight and what is their importance?

Watch-wher is a winged beast with a lengthy body, who saves Lessa's life when she is a child. From the start, the little girl and the beast can read each other's thoughts, but Watch-wher is trapped with the chains of its imprisonment. Whatch-wher warns of danger and is completely devoted and loyal to the little girl.... though their bond is a secret they keep between them.