Jack Skellington is the protagonist of The Nightmare Before Christmas, where he attempts to take Santa Claus's place delivering presents. Eventually, he saw the error of his ways and decided to go back to planning Halloween.
When the Keepers attempt to go back in time, Jack, Sally and Ebsy attempted to stop them. Though Jack could not speak, Sally spoke for him, trying to keep the Keepers safe. Mistaking Jack for an Overtaker, Willa expressed disapointment as Jack was meant to be a hero.