Dust!Sans/Dusttale

Dust!Sans is the brother of Papyrus. To stop the human from killing everyone over and over, Sans is forced to increase his own LV. Killing one monster isn't enough EXP for him to defeat the child, though, and oddly enough, the resets don't send him back to LV one. He forgets his original purpose, and kills everyone, including Papyrus. He begins to hallucinate a much meaner Papyrus who's just a floating head and hands. Sans can also locate SAVE points and destroy them.

"'I even killed all my friends and family, just for you, Pal.' - Dust!Sans"

Story
In this AU, Sans tried to stop the genocide committed by the human by all means, but ultimately fails. Though, through unknown means, Sans gains possession of

DETERMINATION.

Because of this, Sans tried to kill the human and end the genocide and the RESETs once and for all, but yet again, he failed. The human soul was too strong for Sans. So he decided to sacrifice the other monsters to get himself more LV. Sans always felt tremendous guilt, and all the monsters return to him in his nightmares. However, he continued to kill, and eventually it disappeared. The guilt vanished.

At that moment, the only thing that mattered to him was putting an end to the human's tendencies yet again, but this time on a different playing field. Soon he had to kill his brother, Papyrus. Papyrus was the last monster that Sans had to kill. Even though Papyrus was his loving brother, Sans felt that he needed to kill him in order to beat the human. He also makes the argument that it'd be better to be killed by him than the Human. It was the last and most severe blow to his mind. Finally, after killing his brother Papyrus, Sans becomes insane. Since then, Papyrus' ghost has haunted him.

Through the psychological and Physical torment Sans had to face, Sans finally achieved the strength to kill the human. but at a great cost. His friends, his brother. Sans fell into a madness killing everyone he loved. Nowadays, Sans has nothing but LOVE.

Appearance
His clothes are covered with the dust of the monsters he has killed. Sans wears a blue hoodie with a white hood. The "iris" of his left eye is a deep red while the pupil is a blue color, making the vapor trail given off by his eyes a purple color as is a mixture of both red and blue. He often chats with a specter resembling his brother, Papyrus, which is only visible to him. That could be due to him falling into insanity and this specter either haunts Sans or is a way to cope with him killing his brother. The specter has no body. It only has a see-through head of Papyrus with red eyes, floating red gloves, and his scarf.

Personality
After killing all of his friends and family, Sans has grown too overpowered and has lost some of his emotions. He is still lazy but now insane and Determined. He still feels depressed what he had done but he had to do it in order to stop the human.

Bone Manipulation
Sans can manipulate purple bones to his will. This attack is his main and what he usually spawns. He can also make his purple bones sharp, doing more damage.

Gaster Blaster
Sans can summon a stronger version of his Gaster Blaster. It shoots out a purple ray and does a lot of damage.

Telekinesis
Sans has the ability to use telekinesis on you, regardless of soul traits.

DETERMINATION
Sans, now having DETERMINATION, is now stronger and can last longer than the original version of Sans. The attacks he summon can be faster and it also allows him to see SAVE Stars.

Mad Time Mode
As shown in phase 2, Sans can unleash his full power and if he does that, his health would surge powerfully. His attacks would also be much more stronger and he will start to use his attacks more aggressively.

Save Point Destruction
Due to Sans gaining DETERMINATION, he is now able to see SAVE Stars. He can destroy them if he wishes to.

Tiredness
If you continue to slash your knife at Sans, once he runs out of stamina, it is a good chancew for you to strike with your hardest strength. But be careful, Phantom Papyrus can kill you when your off guard.

Phantom Papyrus
Sans relationship with the ghost of Papyrus, mostly known as 'Phantom Papyrus' is pretty nice. Phantom Papyrus usually supports Sans if he needs to and will often protect Sans.

Horror!Sans
Good buddy. They often work together to kill other variations of themselves. (Not Canon)

The Human
His biggest enemy. Sans hates the human for what she has done and how she forced Sans to kill all of his friends and family.

Trivia

 * Dust!Sans carries the ghost of Papyrus with him.