"Sans, come meet your new brother."

The young skeleton blinked and looked up at his mom in confusion. As far as he knew, he didn't have a brother, and not because he didn't want one - but because their family was bunch of skeletons and, well, whoever heard of a pregnant female skeleton?

Not questioning it, however, the boy in blue got up from his bed and walked over to the taller skeleton, titling his head when he saw his mother holding a blanket, smiling down at it.

"B-brother?" Sans whispered, getting his mother's attention. His mom looked down at him, smile, and bent down low so Sans could see his new baby brother. Peering into the blanket, Sans stared at the smaller skeleton, who was busy sucking on his boney thumb, fast asleep.

"His name is Papyrus. Say 'Hi papyrus'." She said. Sans blinked and look down at the baby.

"Hi paperus." He said, causing the female to giggle.

"Well, it's not like I had expect you to get his name right on the first try. Come on, let's take him to his room." She said, standing up and grabbing Sans by his hand, and lead him to the baby's room. Oddly enough, the room was a peach color instead of a normal, sky blue like normal baby rooms for boys. Placing the baby down, his mother grinned at Sans. "He's going to be looking up to you, Sans. You're the only sibling he has. Are you going to be the best big brother Papyrus is going to have?"

Sans looked at his mother and nodded.

"That's good," She muttered, patting Sans on the head. "I know he's going to be in good hands with you. You won't let anything happen to him, right?"

"Right," He said, looking down at Papyrus. "Sleep tight bro, big brother Sans will be here when you wake up."

"You're so fussy," His mother said, frowning as Papyrus continued to squirm in her arms. "You just ate, I have given you a bath. What more could you want?"

As if hearing the complaints, Papyrus muttered, seemingly in a pout, as he continued to move around in his mom's arms. She sighed and began bouncing Papyrus, in hopes that he would calm down. Meanwhile, Sans, now a bit older, walked into the room.

"Hey mom, do we have any ketchup?" He asked. Hearing his brother's voice, Papyrus giggled, reaching his arms out and made a grabbing motion towards him. Seeing this, their mother smiled.

"I believe it's in the cabinet. Also, Sans, your little brother want you to pick him up." She said, smiling, only to frown when Sans began to drink the ketchup. Looking over at his younger brother, Sans smiled and shrugged his shoulders.

"Sure, I'll give him a ride. Let's go, paperus."

"It's Papyrus." His mother scowled gently, but by then, Sans wasn't listening as he picked up Papyrus and began walking out the door.

"Hey paperus? Want some ketchup?"

"Sans!"

His brother was injured. He didn't know how, considering they were made out of bones and shouldn't be able to feel pain, but he was. He could feel it.

Sans had been laying in his room, napping, when a shrill cry ring through the house and without even realizing what he was doing, immediately appeared in Papyrus's room to spot the little skeleton on the floor, arm bent out of shape. He winced when he saw that, knowing that even as a skeleton, twisting any kind of bone in any part of your body hurts like hell.

"Hey, hey, no more crying. Big bro is here." He said, gently picking him up and literally teleported into the room where his mom was. "Mom, Paperus twisted his arm!" He shouted, startling his mother.

"How did that happen?"

"Dunno, he was on the floor when I came in." Sans said, to which his mother blinked at.

"Floor? But...I put him in his crib for his nap." She said. Both of them stared at the still crying child in Sans's room, both amazed and maybe a little bit startled at the fact that Papyrus was able to climb out of his crib all on his own. Using one of his fingers, Sans wiped away Papyrus's tears and smiled down at the boy, who was starting to sniffle.

"You're just full of surprises, aren't you, Paperous the Great?" He asked. Papyrus whimpered, and dug his head into Sans's neck, tears slowly coming to a crawl. Sans sighed as he felt his brother getting heavier, as his mom worked on his arm. His mother smiled at him.

"Papyrus The Great. Somehow, I have a feeling he's going to let this go to his head if we told him what he did as a baby." She said, making Sans laugh.

"Better not to tell him then." Sans winked as his mom, who giggled.

"Sans!" A voice yelled out, cheery as plain as day. At first, Sans wasn't sure who had called him, considering the voice was new and unfamiliar to him, but when he look down and saw his brother looking up at him with the same cheerful expression as the voice, a smile formed on his.

"Hey, buddy, looks like you can talk now." He said. Papyrus giggled.

"Silly Sans!" He said, reaching out his arms to be picked up again. Sans couldn't help but indulge the little brat and began to sit down on the couch.

"I'm silly? You're the silly one, silly bones." He said, making Papyrus giggle once more.

"Sans's silly. Silly Sans!" He squealed, clapping his hands together. Sans couldn't help but laugh, jiggling his younger brother on his leg.

"You're silly."

"No, you're silly."

"No, you are."

"No, you."

"Nope, you're the silly one here, little bro."

"Nuh-uh, you're silly Sans. Silly Sans!" Papyrus squealed, clapping his hands together once more. Sans just chuckled as he brought Papyrus up closer to him.

"Yeah, well, Silly Sans is going to sleep. Want to join?" Sans asked. Papyrus just giggled once more.

"Sans is always sleeping! Sans needs to go out and play! Play with me!" He said, pulling on Sans's jacket. Sans faked a groan of frustration and tilted his head back.

"But, I'm soooo sleepy. Come on, let's take a nap!" Before Papyrus could protest, Sans had pulled him close and under him, fake growling, which caused Papyrus to laugh out once more as he struggled to get out of his brother's arms.

"No, no, no! I don't want to go to sleep! Play with me Sans!" Papyrus squealed, laughing again. As the two tussled around the couch, eventually, Papyrus' energy started to drop and soon, sleep took over, and before long, the two brothers were fast asleep on the couch, where their mother had found them and smiled at the touching scene.

"You're the only sibling he has..."

Sans open his eyes and found himself staring at his ceiling. Downstairs, he can hear Papyrus moving around, trying to cook for their unsuspecting houseguest, and the skeleton was pretty sure he was mumbling to himself.

Not a day goes by that Sans missed those simpler times, when he'd first met Papyrus and somehow became his world. Then, maturity came, things happen, time traveling appeared, and Sans was no longer the hero Papyrus saw, or at least, that's what it felt like. Still, it's not like their bond went anywhere - Sans was still lazy and Papyrus was still Papyrus. Sans still joked around and despite his front - aye - Papyrus still loved it. Papyrus still counted on him for things and Sans never failed to pull through. All in all, their relationship was still good.

"just because i can't hold you anymore, it doesn't mean i won't treat you like you're my little brother. because you still are, no matter how much you think you aren't." He had said once to Papyrus. The reaction he got from that was slightly unsuspected, and yet still warms his soul to this very day.

"OF COURSE SANS. I NEVER DOUBTED YOU AS MY OLDER BROTHER. BUT I WOULD STILL LIKE SOME RESPECT FROM YOU, Y'KNOW? NYEH EH EH EH EH!" Of course Sans respected his wishes, and whenever Papyrus asked him to do something - "SANS! COME PICK UP YOUR DIRTY SOCKS!" - he would do it. - "DON'T MOVE IT THERE! MOVE IT TO YOUR ROOM!" "ok". After all, a trade for a trade, right?

Right.

A/n: May continue it, or may not. Not sure. Just really like the idea of a background story for Sans and Papyrus, they are so awesome :D