Jeff came into work early that morning. He had been doing so for the past few months so he had time to check on Sans before getting to work.

He also had a few things to say to Gaster.

When he came into his workspace, though, to drop off some stuff at his desk, though, he found there was a note there. He recognized it instantly as being from Gaster; the Royal Scientist's handwriting was beautiful and elegant when writing in Hands, but he had never really taken the time to learn how to write well in the Roman alphabet. (His main response whenever anyone asked why was usually along the lines of "I'm the boss here, so everyone else should obey me and learn how to read Hands.") The letter on Jeff's desk was written in Gaster's poor Roman alphabet handwriting.

So he set down his stuff and picked up the note, beginning to read.

I'll be gone for a few days. Take care of Sans. Do NOT take him from the 10th floor. You are relieved of all your other work until I am back.
-WDG

Jeff blew out a slow sigh. Happy as he was that he got to tell Sans that there would be no experiments, at least for a few days, he knew that Gaster was probably up to no good.

Well. At the very least, he might as well make the best of the time he had.

So he hurried to Gaster's lab. Luckily, Gaster had not forgotten to leave the door unlocked.

Jeff opened the door to Sans' room quietly. Sans was lying on the bed, hands folded behind his head, eyes closed. Jeff walked over and sat on the edge of the mattress. Sans cracked open one eyesocket to peer at Jeff.

"mornin'." He sighed, before closing his eye again.

"Sans. You're gonna like this."

"huh?"

"Gaster's gone for a bit. No experiments for a few days."

The edges of Sans' permanent grin lifted just a little as he looked up at Jeff. "cool. that's great."

Jeff thought, not for the first time, that Sans looked more weary than any fifteen year old should ever look. "Yeah. He also said I need to 'take care of you' while he's gone, which I would assume means I get to stick around all day."

Now Jeff could tell Sans was smiling for real. "that's awesome."

Jeff smiled. "Yeah. You wanna go get some food?"

"... yeah."

~o0o~

Four days passed unfortunately quickly.

In this small reprieve from the hell that had become his life, Sans smiled and laughed more than he had in the last year.

The worst part of it, aside from the end, was when Sans first came into the break room and opened the refrigerator. There, on the door, same as always, was a bottle of ketchup, and beside it, one of mustard. It only served to remind him of that day.

He knew that Gaster had likely drugged both the ketchup and the mustard, but it had been the mustard that did it.

He took the ketchup bottle.

When Gaster finally came back, both Sans and Jeff were in the break room, talking about anything and everything that came to mind, simply enjoying the fact that neither of them had to do anything.

That is. Until Gaster swept into the room.

Both of the two monsters froze, looking for all the world like deer caught in the headlights of an oncoming car.

For a moment, Gaster just looked at them. At the ketchup bottle in Sans' hand, at the plate of leftovers in front of Jeff. At the fear on their faces. Then, "Sans. Come. Jeff, you can return to your job."

"But-"

"Now."

Sans reluctantly stood and followed Gaster out the break room, Jeff still muttering quiet protests behind him.

Gaster led Sans down the hall and back to his lab-- Sans had not set foot in there since leaving it the first day with Jeff.

When they walked in, Sans almost immediately noticed the the small shape on the operating table, twitching incessantly

"is that-..."

Gaster motioned him over. Sans saw it was indeed a small skeleton, but in it's chest was not a whole Soul but what appeared to be a fragment, glowing a soft white.

"This is DTW Subject-643. And, as you seem to have nothing better to do than laze about when you're not with me, you'll be taking care of it."

Almost hesitantly, Sans reached out a hand to S643. "Where..." he trailed off.

"You are from my left hand," Gaster intoned, "it is from my right."

Sans watched, enamored, as the small figure shivered at his touch. Then he paused, looking up at Gaster. "wait... so... he's my brother?"

Gaster scowled. "No. You and it, not he, are both my clones, and test subjects for the DTW project. Nothing more."

Sans blinked a little more, then looked back to S643. He remembered Jeff telling him that Gaster was wrong, that he was so much more, and he knew, just like him, S643 was more than a test subject.

"he's my brother." Sans whispered quietly, tickling S643's sternum with one finger. S643, eyes still closed, made a face and tried to wiggle away.

Gaster sighed irritably. "You are just as bad as Jeff."

Sans ignored Gaster. "an' i really get to take care of him?"

"It, Sans. Yes, you'll be taking care of it. I will show you how to make the food solution for it, along with the dosage size... for it, and yourself at the same time, I think."

His grin stretched as wide as it would, Sans just reached out to lift S643 off the table, cuddling the small skeleton to his chest. S643 snuggled against him, instinctively seeking out the warmth of Sans' Magic.

"...my little brother..."

~o0o~

Despite his irritation with Sans for the whole "brother" business, Gaster was pleased. Sans had responded to S643 exactly as Gaster had wanted, and in the past few weeks, Sans maximum HP had risen back up nearly to what it was before.

Granted, Gaster had lost another chunk of his Soul for it, but that was a small price to pay.

There was only the small problem of Sans becoming too attached to S643. He talked to it constantly, murmuring in a voice just beyond Gaster's hearing, stopping whenever Gaster was in earshot, and he carried it everywhere. He was always snuggling it and playing with it-- when it wasn't sleeping, and despite the fact it had yet to even open its eyes. Gaster had been a little worried that Sans might accidentally damage S643, but Sans quickly proved himself to be beyond careful with it.

Now, for the most part, all of this was okay, all things Gaster could deal with. The problem came with Sans not trusting Gaster with S643. He was scared, apparently, that Gaster would start using S643 for the DTW experiments.

Because, evidently, the ID of "DTW Subject-643" wasn't a dead giveaway.

The realization of Sans' distrust came only a day after he had been given care over S643.

Gaster had been going to get him for the next phase one injections.

He unlocked the door to Sans' room, and walked in to find Sans sprawled across the bed, S643 curled up on his chest.

When Sans noticed Gaster come into the room, he sat up, clutching S643 to his chest.

"Sans. Come. It's time for the phase one injections."

"but what about my brother?"

That was another thing. Sans refused to call it S643.

"What about S643?"

"i don' wanna leave him alone. i'll be gone for a long time, and something might happen to him."

Gaster shook his head. "It's not yet developed enough to move more than twitching. It is incapable of getting into something."

Sans just tightened his grip on S643. "something might happen to him." He repeated, staring at Gaster.

Gaster sighed. So that's what this was about. Fine, then, if Sans was so determined to keep S643 away from the DTW project. It wasn't like that was the reason it had been brought out of suspension, anyway.

Not that Sans knew that.

"Sans, so long as the first test subject is fully functioning, I will not need to experiment on the second. That is the reason for its existence; a backup in case something goes wrong with you. And, if I were to begin experimenting on it, and something were to go wrong with you, then who is to say I wouldn't have already made the same mistake with it that I made with you?"

The deal was veiled, but Sans understood it immediately: if you cooperate, if you do everything I say, then S643 won't be used instead of you.

So Sans slid off the bed, carefully tucked S643 under the covers, and followed Gaster out of the room.

~o0o~

Jeff knew that Gaster had planned one experiment or another today, but he didn't know when exactly the experiment was. Because of that, when he came to check on Sans, they had already finished with what they were doing some several hours ago.

As Jeff came into the lab, Gaster glanced up at him, but said nothing.

Jeff continued on to Sans' room. When he stepped in, he saw Sans was curled up in his side. Normally, whenever Gaster finished with Sans, he simply left Sans lying on his back on the bed.

As Jeff approached, he saw Sans was curled around something...

It was another skeleton.

Sans was hugging another skeleton to his chest, clinging tightly to the smaller figure. Both were sound asleep.

Jeff just stared at them a moment.

Then he backed out of the room, and turned to Gaster. "Why is there another one?"

"Hmm?" Gaster didn't even look up from his work.

"There's another skeleton. Who is he, and where did he come from?"

Gaster finally looked up at Jeff. "It is DTW Subject-643. The clone from the matter of my right hand."

Jeff frowned. "You made another one?! Isn't it enough that you're already torturing Sans?!"

"Jeff." Gaster's gaze bored into Jeff. "First of all, I had already created it, and only just brought it out of suspension a few days ago. Second of all, I did it at your suggestion."

"At my--!?" Jeff spluttered. He would never have suggested bringing another child into this science experiment hell.

Noticing Jeff's surprise and horror, Gaster continued. "Yes. S643 is under Sans' care. You did suggest giving Sans something to care for, correct?"

Jeff's mouth opened and closed. He wanted to say, but this isn't what I meant! but he knew that it was. Granted, he had been thinking more along the lines of a puppy or a kitten or something, but of course that was foolish. Gaster would never have let an animal into his lab unless it was for an experiment.

Knowing he didn't have much of a say in the matter, Jeff just sighed and shook his head.

~o0o~

Sans woke up much more quickly than usual this time.

Perhaps it was because he had already been resting for a while, or because he was beginning to get used to the dosage size Gaster was injecting him with, or maybe because Jeff was using extra healing Magic.

Or maybe it was because he had his brother curled up in his arms, because he was aware of the small life tucked against him, because he could feel the Magic of the smaller skeleton, so similar to his own, because he could feel the small, growing, almost-Soul beating alongside his own.

Had anyone asked Sans, he would not have been able to describe it.

It had just been an instant thing. The moment he had seen his brother, he had fallen head over heels in love. With all his Magic, all his life, all his Soul, he loved his brother. He always would love his brother, this other life that clung to him, sleeping pressed to his chest.

In those moments that Gaster had given care of the small skeleton to Sans, Sans had promised his brother and himself that he would do his very best. He would always be there, and would always protect his brother, always love him, always just... be there.

And he wouldn't let anything hurt his brother. He promised.

He couldn't have said why. He just did. He loved his brother.

He always would.

As Sans woke up, Jeff easing the lingering stiffness from the injections, Sans' brother stirred a bit in his arms.

The little child didn't have a quite fully-growth Soul yet, it was still just a fragment. But Sans could already see it had gotten bigger since leaving for the injections.

He gave his brother a squeeze before starting to sit up. He smiled at Jeff, the edges of his grin lifting.

Jeff smiled back, then gestured to the figure in Sans' lap. "Who's this?"

Sans looked down at his brother, snuggling him a little closer to his chest, rubbing one hand over his skull. "my little brother. he doesn't have a name yet, i'm still trying to figure out what it is."

"Ah. Right, I remember you telling me naming skeletons was hard."

Sans nodded, still looking at his brother. "gaster says he's "s643," but i'm not gonna call him that. i'm never gonna call him that."

Jeff nodded a little. "That's good. He's more than just a test subject."

Letting out a small sigh of contentment, the still-sleeping figure shifted a little in Sans' arms, snuggling closer to Sans' chest. One hand curled into a fist, grabbing up a handful of Sans' shirt.

Jeff could easily see that Sans was completely enamored with his brother.

Slowly, Jeff reached out, gently rubbing a hand against the smaller skeleton's skull.

"You're going to be a great older brother, Sans. I can already tell."

§

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