Sans

Sans is known to be very lazy and laid back, sleeping on his job and taking constant breaks. He likes to make bad skeleton-related jokes, although the fact that he performs at the MTT Resort proves to be a fake, saying that if it weren't for the promise he made to Toriel he would have killed Frisk. He likes science fiction and loves to drink ketchup. Also, he hates making promises. He is gentle and reassuring but gets very serious at times, sometimes making his pupils disappear leaving black spaces. He is also very observant; his phrases and actions change according to the player's actions more than the other characters. Sans' laziness seems to be in fact a combination of fatality and apathy. He wonders if his laziness stems from his knowledge or in fact any progress he makes will be abruptly erased as the timeline resets.