Undertale Boiz x Reader

Responsibility [Science!Sans x Scientist!Reader]

I inspired myself with my own Undertale AU I created called GleeTale. If you haven't seen it, go check it out. Wow, on the third to last oneshot I'm shamelessly self advertising. Way to go me! Anyways, here we go.

Experimentations in Doctor Gaster's lab didn't just focus on determination. You were one of the only scientists who wanted to focus on other aspects that could be far more powerful than determination alone. And not one of the other, less powerful aspects from human souls. Oh no. You had theories about all different kinds of aspects hidden in MONSTER souls that could rival the seven human aspects.

Let me Explain. Humans carry seven traits that each can be a vessel of. In order of most to least powerful. Determination is the strongest. The second strongest has to be kindness. Then perseverance, which is extremely like determination. After that is Bravery, Being the boldest of the traits. It is the most equaliberum Of the traits. Justice is next because the sense of justice can be deluded by bias. The second weakest asset is integrity. The weakest is patience, because it's not always a good thing. 

What you studied were traits in monsters that could rival these seven traits. There were how many main monsters in the underground that all the fallen children interact with in the Omega timeline? That's right. Seven. Papyrus, Sans, Toriel, Alphys, Mettaton, Asgore, And Asriel/Flowey. If each of these vessels contain some sort of trait that goes completely against or matches these human traits, then that could be something revolutionary. It would give a new power to the monsters, finding an alternate way of breaking the barrier.

You proposed the idea to Doctors Gaster and Alphys, but both of them shrugged you off. Alphys, who didn't beleive in the multiverse theory, said basing your theory on another theory is unreliable. Gaster said it was unthinkable and he had experimented on willing monsters souls before. And nothing would work. The only mosnter who would beleive You was Sans, Gaster's oldest son.

"If what you say is true, then you can use me To find my aspect? Then if we do that, we can prove to Dad and Alphys you're right!"

He was optimistic about your project, that's what you loved about him. You nodded and agreed to stsrt the experimentation. You would conduct as much research as you could on the omega timeline. You couldn't talk to Gaster yourself or he would find out about your secret research that's he finds irrelevant. You had Sans ask about his theory all the time, gathering evidence about the Omega timeline.

You were around Sans often, almost too often. So often that Alphys asked if you Two we're a thing. You didn't know what to do. Sans took the lead and said they were. Gaster happened to pass by and he became suspicious. Sans began holding your hand and you kissed his forehead. You were together! See!?

After that it was okay for you two to stay together after the lab was closed, hang out with him after to see his reactions to various stimuli, and see his day to day life. By comparing him to his Omega timeline self, which is him older and after Gaster supposedly conducts an experiment involving his theory and DETERMINATION where he becomes depressed, learning everything and knowing everything. 

Let's see, after he becomes self aware and more alone he continues to idolize his brother, who is still a baby bones right now, and he takes a lot of things into his own hands. He keeps things to himself and takes care of a lot of things. Mostly done at night so that's why he's always tired. He's also always tired because he carries the weight of awareness on his shoulders.

It was late at night when you made this discovery. Sans had his soul out, which was confirmed to be a cyan blue. With that proof he was supposed to rival the soul for PATIENCE. That's when it hits. You gasp  causing him to jump.

"Sans! Responsibility! Your aspect is responsibility!"

Sans grinned his skeleton grin, pushing up his glasses. He looks at the notes you've taken. When putting it all together it did make sense. He looked at his soul, shimmering the same colors as patience.

He can't wait to prove this to Dad.

Lol headcannons. Gotta love them amirite? Also no more requests in this book. It IS the last two oneshots anyways! Lol sorry not sorry but wait I'm actually sorry.

~Eva