It's long, but please read if you'd like.

Appearance His basic clothing is the same as the original, but the dust of the monsters he killed is stuck to his jacket. He wears his hood up, and his pupils change significantly when his abilities are active. Since he has lost his sense of justice, his pupils no longer glow yellow; they have gradually turned red due to his Determination to kill the Player. Furthermore, by mixing with the original light blue representing Patience, they sometimes appear purple. His height is the same as the original Sans. Abilities He does not lose his memory even after a reset and is aware of everything regarding Saving, Loading, and Resetting. In other words, the concept of the "N-th cycle" exists for him as well. He becomes more powerful as his LOVE increases; because it has risen significantly, he does not die easily. His ATK and DEF have increased. However, since EXP and LOVE are initialized upon a reset, he must kill the monsters to raise his LOVE every time. Only his LV has increased; his Soul has not changed. He does not hesitate to use underhanded methods. He uses bones as before and may generate sharp bones. His melee combat ability has also improved. The Gaster Blasters basically look the same as the original, but the pupils are different, changing between red, light blue, and purple. The lasers remain white. Because his HP has increased, he can endure hits, though he still dodges attacks. Since he understands the game system, he sometimes destroys Save Points, Dimensional Boxes, and Shops. He has no interest in destroying buildings or walls. Note that while he is aware of resets, he cannot use Determination himself. He can still use KR (Karmic Retribution). Overview It originally started with the idea of "sacrificing the few for the many." Even the cruel act of killing monsters to raise LOVE was painful, but as those cycles repeated, he drifted further from himself and fell into madness. In the early cycles, he felt strong guilt and remorse, but this faded as the cycles continued. He eventually justified it by thinking that since everything would be reset anyway, killing them wouldn't change anything. Killing his beloved Papyrus was the most painful, but he justified it as being better than having him killed by the Player. The death of loved ones, the murder of his own kin including his brother, guilt, obsession, confusion, and the countless resets encompassing all of it—that is how he broke. As a price for his sins, he began to be plagued by horrific nightmares. Scary things, sad things, and even ironically happy things. He stopped sleeping to avoid those nightmares and is now an insomniac. He still tells jokes, but he doesn't enjoy them as lightheartedly as before. Since he is desperate to stop the Player, he can no longer be called lazy. He commits massacre over many cycles to stop the Player alone; rather, since he was the only one who retained memories, there was no one to cooperate with him. And as he repeats these cycles, his understanding of his victims deepens, allowing him to kill them more easily than before. He enjoys madness, cruelty, and slaughter; having become a madman, he can be called unpredictable. However, he hasn't completely lost his sanity; he still possesses emotions and can even feel fear. He has a particularly strong fear of what comes after death, filled with anxiety about things he has no way of confirming. Ironically, he also seems to fear the possibility of the Player never appearing again. Even if he kills the Player, he likely waits until the next Continue or Reset occurs. In short, he hates being treated as a toy by the Player, so anyone who tries to rob him of his freedom can become an enemy. Also, he does not engage in torturing his opponents.

He has no interest in absorbing monster souls or the six human souls. In the first place, since they are cleverly hidden by Asgore, he would not know their location. His goal is not liberation to the surface or gaining power, but simply to stop the Player at all costs. If the Player shows Mercy, he immediately becomes enraged, as it feels like an act of deception. Furthermore, if the Player tries to pursue a Pacifist route, he will stop them with all his might. He understands that the "True Reset" after a Pacifist route is powerful enough to erase Flowey's memories, and he doesn't know what might happen beyond that. Ketchup remains his favorite. He never changes his dust-covered jacket; it's difficult to find clean new clothes, and he has no one to show them to anyway. He wears his hood to avoid showing his face to others and to keep dust from getting in his face. He still cherishes Papyrus. His birthday is February 10th. He apparently reads books sometimes (Sci-Fi and Fantasy novels). He seems to drink alcohol quite frequently; if the Player isn't around, he'll drink until he loses consciousness. He prefers strong spirits like vodka.

Not Frisk or Chara. Chara is no longer involved in the story of Dusttale. Everything depends on the Player. Sans does not call them "kiddo" or "brat," but refers to them as "Human" or "Player." Possessing strong Determination, they can use Save, Load, and Reset. They have a pitch-black face, gray clothing, and white hair. They are the one who broke Sans through excessive slaughter. They are a dedicated player trying to see everything in Undertale.

A hallucination that Dust Sans began to see due to the guilt of killing his own brother, Papyrus. Since it is a hallucination seen by Sans, it is invisible to other characters. Only his head, gloves, and red scarf float in the air; he has no torso. His eyes are red, and he is always smiling.