The Sans of the Undertale AU, Ancienttale.

One of many Ancient monsters hiding among mortal kind to keep from preying eyes, Sans, AKA Atlas outside his world, is one 'cool cat' to practically literal sense. As an Ancient of the North Star, his arcane is naturally chilling cold yet his personality is very warm and welcoming to those who he sees to be his allies. However, don't let his fluffy exterior fool you, as behind that powdery white fur is a highly skilled hunter of the guild. He can be calculating, sharp and much like a leader when he sees it necessary. His hunting weapon of choice is a Blaster Bow of which he shoots frozen stars as his arrows.

Over all he is a kind hearted fellow if also quite sarcastic as well. He likes to joke and play about with others for making more good, memorable times to outweigh the nightmares that still weigh heavily in his mind. He does what he feels is best for himself and his brother, who is all that remains of his family to his knowledge. Even if it means continuing to live their fake lives for the sake of their happiness.