It's ironic most people would call him the little brother.

Sans honestly did not know what to think about that. Maybe it was because of his height? Nah, it can't be it. Maybe it was a his bone-crackling sense of humor. Yeah, that had to be it.

But in any case, Sans often been called the little brother when he was usually around with Papyrus. Which...was not all the time, but for the most part, wherever one skeleton goes, the other can't be too far behind. So it really says something when neither could leave the other's side for a minute.

And especially Sans.

Sans was a lot of things; he was lazy, he didn't like work, his humor was either a hit or miss depending on who you talk to - and with Papyrus, it was always a miss, even when he's smiling - and Sans was just in general a laid-back person with a cute sense of charm. This is usually how the people in Snowdin had taken a liking to him, seemingly more than Papyrus. With a wink, a smile, and a bad pun, Sans pretty much had life under his control.

Unfortunately, life was not that kind to Papyrus.

The taller skeleton had been trying desperately to get into the Royal Guards, but as it turns out, the taller was too...kind-hearted for such a thing. Neither Sans nor Undye had the heart - JOKES - to tell Papyrus the reason why he'd never made it to the Royal Guards. For Sans, Papyrus was pretty much a kid who took light of a situation, any situation, and no matter how bad that situation may be, Papyrus was there to cheer you on, essentially.

Heck, he couldn't even capture the human he'd been rambling on about, and Sans knows just how long Papyrus had been waiting for one to show up so he could. Instead, he and the human became friends, which Sans was eternally thankful for. Sans had been getting a lot of recognition from folks that he would otherwise ignore. He, though never saying it out loud, always felt bad when someone address one and not the other. Undye was Papyrus's friend more than Sans, and of all the time he and Papyrus had been stuck here, in this neverending loop, that was probably the only friend Papyrus was going to have.

Goddamn timelines.

So, Sans kind of made it his mission to help his brother out, in his own, lazy, way. Yes, there was the promise he'd made to Toriel, but it was more or less for his brother than the promise. Both mean well, and Sans will always hold her close to his chest, but Papyrus was the only thing he had since they had appeared in this world, and it kills him every time Papyrus was happy, and I mean truly happy, he was ripped away from that happiness because of the timelines that kept getting reset, and they would have to start over.

And, it was especially painful if the kid was not Frisk, but someone else. Always a different name, but always the same face.

And it took everything in Sans's power not to flat out murder Frisk whenever he was around. Because Frisk and the Fallen Child were not the same. Frisk didn't LOVE, and got love in return. The Fallen Child, on the other hand, cared less for the feeling of love, and more about the power of LOVE. The Fallen Child would murder Papyrus in a heartbeat...not Frisk.

But, as I said above, it was a neverending cycle. Every time their world got reset, the path changes constantly, and Sans was never sure which path was going to be the Fallen Child or Frisk. And ever time, Sans worried for his brother, because then he would die again and again and again and again, and Sans had to live with that. Constantly. Every day. Fearing another reset, fearing someone using DETERMINATION.

At the end of the day, Sans can't afford to care.

But...his brother's face, whenever Frisk was around, was worth it. He was always so happy, so cheerful, and no matter much Papyrus says he hated it, he would always smile whenever Sans cracked a bad pun or two. That was all Sans lived for.

" hey, papyrus..." Sans started it. Papyrus turned to his brother.

"YES SANS?"

" could you, like, do me a favor?" When Papyrus didn't say anything, Sans continued. " could you like, promise me that...you'll keep smiling? no matter what happens?"

"SANS THAT IS RIDICULOUS...! OF COURSE I'LL KEEP SMILING. I AM A SKULL AFTER ALL, THIS IS THE ONLY EXPRESSION I CAN MAKE!"

"...right..." Sans said, before shuffling around, hands in pocket. " welp, i'm going to grillby's. you want anything?"

"HOW MANY TIMES DO I HAVE TO TELL YOU NOT TO EAT THAT JUNK FOOD?! I'LL MAKE US SOMETHING TO EAT. STAY RIGHT THERE."

"ok."

With that, Papyrus began walking towards their home, which really wasn't that far from the restaurant. Sans didn't question Papyrus's logic, he never really does, and maybe that makes him the best big-little brother Papyrus has. Eh. He was the only big-little brother the bonehead had, so it doesn't really count to the best, now, does it? Whatever.

Sans sighed, closing his eyes.

" yeah...i can't afford to care...anymore. just...please, keep smiling...i want to see you happy...when you're happy, i'm happy...Papyrus..."