Quil Ateara III, also known as "Old Quil", is the son of Quil Ateara II, one of the three original wolves who made a treaty with the Cullens, the grandson of Quil Ateara I, the husband of Molly Swan, the father of Quil Ateara IV, the grandfather of Quil Ateara V, the uncle of Sarah Black, and the great-uncle of Rachel Black, Rebecca Black and Jacob Black. He is a member of the Quileute tribal council and a resident of La Push.
Quil is one of the few living members of the Quileute tribe alive at the time of the previous pack. After Sam returned to the tribe, Quil read the high temperature and his growth spurt as signs of his phasing. He explained to Sam what had happened to him and taught him everything that had been passed down through the generations about becoming a wolf. He along with Billy Black and Harry Clearwater saw their grandfathers change into wolves, but 2 generations skipped phasing because there were no vampires, so the wolf gene wasn't triggered.
After the passing of his son Quil IV, he spent the next decade raising and caring for his grandson Quil V with daughter-in-law Joy Ateara. His responsibilities were added when Sam Uley phased for the first time, and Quil, and Billy Black and Harry Clearwater told him everything. Though his grandson didn't phase yet, Quil had expected him to start at any time, which finally happened in 2006.
In an alternate deleted draft of the New Moon novel, after Jacob Black told Bella Swan to stay away from him (in the deleted draft, he doesn't go to her house to apologize), and Bella later drops by the Ateara's house to visit Old Quil's grandson, but Old Quil turns her away at the door. This makes Bella very uncomfortable with him.
Eclipse features a campfire scene in which Bella, Jacob, the pack and a few other Quileute residents sit at a secret bonfire to hear Quil and Billy tell some of the Quileute legends about Kaheleha and Taha Aki. This is his only appearance in the books other than being mentioned by Jacob Black various times. He is also at the same meeting in the film, but it is Billy who tells the entire story.
He is described as white-haired, brittle and ancient, with a thin tenor voice.