Sans was tired. Tired of innocent monsters dying, tired of crumbling to dust from a single hit, and tired of being too weak to do anything about it.
The 6th child had come through the underground with such a fury that he destroyed everything in his path. He didn't seek out monsters to destroy, but anyone who dared impede his quest of his twisted sense of 'justice' would be shot down. The kid had drawn and pulled the trigger on his old revolever before Sans could even introduce himself at least four times, making him the 7th and final victim.
With being so twitchy fingered, Sans never did find out what his goal was. Since his soul was dominated with the trait of justice, he guessed that the need for revenge might be the culiprt. Maybe a monster had taken his grandfather's life during the war, and the child wanted to seek vengeance. Sans knew that was probably not the case but it at least gave him some explanation for his actions.
Whatever drived that kid through here didn't matter, since he failed on his quest. His soul didn't have determination as his trait, so he only had enough to reset maybe about 7 times. Asgore killed him each time, seemed he never learned from his previous fights with him. Lucky, Sans had tricked Papyrus into going on a training mission with him deep in the woods at the time the kid was supposed to arrive. Papyrus would never be the same if he saw the shopkeeper's husband shot in the street.
But this chain of events had happened before. Even though all six of the fallen humans had failed leaving the underground alive, it sure took them awhile to die. Sans didn't know how much time had been reset before his time with Gaster. The skeletal scientist certainly screwed Sans over in the long term, but he couldn't stay mad at him after all this time. Gaster couldn't have known the side effects of his tinkering.
The experiment sounded good on paper. Turn raw soul essence into magic. Gaster had always valued brains over brawn but he couldn't help but feel jealous of other monsters. His magic was lackluster to say the least, along with Sans, who didn't mind his low stats as much. Nobody could have known that messing with the natural order of things would lead to Sans' low stats of 3 AT, 3 DEF, and 12 HP being drained to the death sentence of 1 in each stat. But he didn't feel that bad, he could have ended up stuck in the void like his mentor, plus it gave him a keen sense of time and space allowing him to even remember resets.
Sans looked at the clock hooked on the wall of his cellar workshop. It was early morning, way too early for Sans. He had told Papyrus he wasn't feeling well so he didn't have to do sentry duty. He hated lying to Paps but this was important. Papyrus will understand once his project is complete. Or think he was mad, this project was extremely dangerous. It was better to stop thinking about that, it was only making Sans more nervous.
Sans was gonna make Gaster proud, and complete his original goal. To become strong, strong enough to protect Papyrus from anything a human could throw his way.
His first problem, Sans was not fit. He could barely keep up with papyrus on his morning jogs. He needed to be able to dogge whatever weapon a human could possibly use. Since his agility wasn't gonna increase anytime soon, he would just have to be able to know when to step out of the way.
This wasn't as impossible as he first thought. During his research on souls with Gaster, they found that the human souls captured by Asgore each had a dominant trait. These traits could give someone certain enchancments to combat skills. Sans should know, he volunteered to be a test subject for it. It was discovered that certain combinations of those traits could give an even more variety of skills. Gaster was absolutely obsessed with the idea, shame the first trial went so horribly wrong.
If Sans wanted to increase his reflexes, he'd need the combination of justice, patience, and the tinyest bit of determination. After a quick raid on Gaster's old lab, he found the ancient research notes and the soul samples he needed.
But Sans had been hesitating all day in his lab. He had put his concoction of emotions into a transperant but sturdy glass sphere. He couldn't just attach this forgien magic anywhere, his body would reject it. The only place that would take it, was his eyesocket.
Sans gripped his skull in his hands. The thought of having to replace his eye made him want to puke his non existent guts out. He would made it quick.
Sans' hands started to shake
All he had to do
Was grab the scalpel
And put it behind his white pupil
That's it.
So close to the magic connection.
The line of magic that supported his eye would just need one small slice.
And the conjured eye would be gone.
His hands were shaking so bad inside his skull, he might drop the scalpel.
He would do it on the count of 3
1...
2...
He took one final deep breath
...3