Jack is the brother of Skull and a major character in Canontale. He first appears in the forest after Ella exits the Ruins. He serves as a supporting character in a Neutral and True Pacifist Route and as the final boss and heroic antagonist in a Genocide Route.
Jack is a short skeleton around Ella's size, he has blonde hair with what seems to be brown highlights, he has blacked out eyes with glowing white pupils, though when serious his pupils will dissapear and when using his telekinetic powers his eye will glow blue and yellow. He wears a white shirt, possibly a tank top with a yellow stripe across the center of it, he wears a dark blue jacket with brown fur lining the hood and the wrists.