|Residence||The Core, Underworld|
Sans is a major character who appears in Grim Tales: Rebirth. He is the current lord of the Underworld, being a supposed neutral entity that is present to prevent quarrels between the realms in the Underworld.
Sans is a short and big boned skeleton, with a perpetual grin on his face. He wears an unzipped hoodie, a white t-shirt or sweater, black shorts with white stripes and a pair of sneakers or slippers.
He has white pupils, which tend to disappear when he is serious. When using magic, his left eye flashes cyan and yellow and his right pupil disappears.
Sans is shown to be very laidback, sleeping on the job and taking breaks often. He enjoys making bad, skeleton-related puns; although the fact that he performed at MTT Resort hints that he may in fact be a talented comedian. He likes science fiction and loves to drink ketchup. In addition, he hates making promises.
He is kind and reassuring but becomes eerily serious at particular moments, sometimes causing his pupils to disappear leaving empty black sockets. He is also very observant. Sans's laziness is shown to be in fact apathy and fatalism. He wonders if his indolence stems from his knowledge of the fact that any progress he makes will be erased abruptly as soon as the timeline resets, though he dismisses it as an excuse for being lazy.
Upon becoming the lord of the Underworld Sans keeps his laziness and appears to not care much about the current Underworld, yet is ready to step in when needed. He made the several realms so he wouldn't have to do much of the ruling, and made sure The Core is a save haven that also wouldn't be affected, should there be a war. Judging by the quantum physics book, workshop, and broken machine found in his house; among other evidence, Sans is heavily implied to come from a scientific background.
He shows deep care for his brother, Papyrus, trying to support him in everything he does, even though they might seem silly at times. He first let Papyrus be the Underworld Lord, but eventually took over and made it that way so they both wouldn't have to do anything. He keeps Papyrus in The Core to protect him from the dangerous Underworld, but eventually decides to let him go with Grim Junior.
Powers & Abilities
Sans is shown to be able to move exceedingly quickly and/or teleport through his frequent use of "shortcuts", as he calls them. In battle, he shoots what appear to be a kind of laser or beam using "Gaster blasters", a device resembling a goat or dragon skull. These also bear similarities to the DT Extraction Machine found in the True Lab, Gyftrot's head, and Asriel's first form's head.
He has obtained the knowledge of multiple timelines and the SAVE function, presumably through his scientific research. However, it appears he does not actually retain knowledge when the protagonist loads a SAVE, and cannot use the SAVE function himself. It may be that his awareness of the situation and his innate perception allows him to recognize when the protagonist is behaving unusually.
Sans is also shown to have some skill in playing the trombone, though he is only seen playing it once. Papyrus finds his "incidental music" annoying, so he must play it on other occasions.