A/N: Alright! This is my first attempt at an Undertale and RWBY crossover! This idea suddenly just appeared in my head and I haven't been able to get it out. So I figured I would just get it out. You know what I mean? Anyway you probably didn't show up just to hear me talk, so without further a doo-doo…

Enjoy!

Sans felt an overwhelming sense of regret and sadness as he slowly turned to dust.

'At least…I'll see them soon.' He thought to himself with a grin. He closed his eyes as he finally faded away into dust, feeling a small sense of contentment.

LINE BREAK

When Sans opened his eyes he wasn't greeted to the sight of his family like he expected. Instead, he found himself lying on the ground all alone. He lifted himself up off the ground to take in his surroundings and saw that he was in a forest.

Sans stood up, but caught a glimpse of his hand while he did so, and almost jumped in surprise. There was skin and flesh covering what was usually bone. He hurriedly felt over his body and found that there was skin and flesh everywhere. He lifted up his shirt and felt his bare skin on his stomach. He saw a large scar going up and down his body diagonally.

'Heh, a reminder huh?' He thought bitterly to himself. He placed a hand on his cheek and pinched it, it wouldn't be the first time he had a dream like this. He didn't wake up though, so it had to be real.

'I'd better go and find some of the residents of this place.' He mused to himself. He set off with that idea in mind.

After a good half an hour of walking he came across a small village. He increased his pace a bit as he got closer and closer to the village, but was stopped by an arrow stopping landing in front of him.

"That was your warning shot! Now state your business!" A male voice yelled to him. He looked to where the arrow came from and saw a group of men with bows and arrows ready to shoot. Sans grinned and raised his hands up to placating gesture.

"I just want a place to sleep." He said. His eyes widened after he heard the sound of his voice though. He sounded pretty young. Apparently the men thought that too, as they were quick to let him into the village.

"Come young one, it is not safe to be about during this time." One of the females in the village said as he was rushed inside of a hut.

"Why?" He asked ignorantly. This was moving a bit fast.

"There are monsters of darkness that will arrive soon. We have already called for help but they won't get here before the beasts. That's why those men are out there, to hold them off." The woman explained. Sans nodded before asking another question.

"So what are these 'monsters' called?" He asked. He was considered a monster not too long ago. He didn't want to see any more of his kin needlessly slaughtered if he could help it.

"They are called Grimm. They are soul less black monsters that wouldn't hesitate to kill even a child such as you." She said. Sans nodded before blinking. There was that little problem again that he needed to look into.

"Last question, do you have a mirror I could use?" The woman looked confused at the question, but complied with his request. She handed him a small hand mirror and he took a look at his face. He was surprised to say the least. He had pale white skin and white hair that reached the base of his neck. His eyes were teal without pupils and his face was younger than he thought it was.

'I look like I did before I ended up as a skeleton. I think I was 12 years old.' He thought to himself, before looking back at the woman.

"Thanks, uh…" He didn't know her name. She smiled softly and answered his unasked question.

"My name is Rosetta." Sans grinned. This lady seemed alright in his opinion.

"I'm Sans." Before any more words could be spoken loud animalistic roars rang through the small village. Sans walked out of the hut, despite Rosetta's better wishes, to get a better view of the action. He saw the men out there fighting black creatures with masks and various pieces of white armor on them. There was what looked like a giant scorpion, and even large snakes and gorillas. The warriors were keeping them at bay but were hard pressed.

"They're not gonna last much longer…" He said mostly to himself. Before Rosetta could even try to stop him, he had disappeared and went to the aid of the men.

One warrior was about to be impaled by the stinger of the scorpion-like Grimm, but Sans arrived in time to save him by pulling him away from the immediate danger.

The man was flabbergasted at the sudden movement but had no time to dwell on it as Sans began to speak.

"Hey there, what's your name?" Sans grinned.

"D-derrick,"

"Well Derrick, tell the other guys I've got this and that they can fall back."

"What? No, you're only a child, you shouldn't be-"The scorpion took that time to lunge towards the two, ready to kill. Before it got too close however, Sans summoned two Gaster Blasters and incinerated the monster.

"I've got this."He asserted and the man only nodded dumbly as he scurried away. Sans' grin widened when he saw no one else was in danger. He put both of his hands in his pockets as he turned to face the Grimm. He felt the familiar red cloth on the inside of his pocket as he did so.

"Alright," As he said this, his eyes lost all the white in them and turned completely black. Then in his left eye a glowing blue iris formed. "Let's get this over with." He sighed.

LINE BREAK

After 10 minutes the Hunsmen arrived to the village to answer the distress signal that was sent. What they saw was only the villagers celebrating their clean victory. The two Huntsmen walked up to the village elder to speak to him.

"Where is the danger from the signal you sent?" One asked. The elder gave him a sidelong glance before focusing his eyes back to the celebrating people.

"I'm afraid you're a bit late for that, it was already taken care of."

"But what was it?"

"A horde of Grimm appeared, we would have all died, had we not have gotten help." The Huntsman looked down guiltily before asking another question.

"Who helped you?" He asked. The Old man smiled as he answered.

"It was a young boy, no older than 12 years if I had to guess." The Huntsmen both looked surprised at that and rather skeptical.

Rather than voice their skepticism though, they chose to ask the question. "May we see this boy?"

"No," The elder refused with a shake of his head and a chuckle. "We offered to give that boy whatever he wanted and he refused. He told us he was tired, so the least we can do is let him sleep after what he did for us."

"What was his name at least?" The first Huntsman asked.

"His name is Sans."

4 YEARS LATER

It's been four years since Sans first arrived on Remnant. He had grew taller than he ever was before, mostly because he was never given the chance to physically grow.

He had taken the time to learn as much as he could about the world as to not raise suspicion about his origins. He was technically an alien, so he chose to be extra cautious.

His attire hadn't changed much from his usual. He wore a blue fur-lined jacket over a plain white T-shirt, with black shorts going past his knees with a white line going down the side. On his feet he wore white socks and black flip flops. One of the only things that were added was the blue and black headphones he wore on his head and the socks on his feet.

He was currently on a plane that was going to Beacon Academy, the school for Huntsmen and Huntresses. If one were to ask how he arrived there, well it was a pretty funny story.

FLASH BACK

Sans had just finished clearing a horde of Grimm. It was relatively easier than it was 4 years ago, but it still left him a bit tired. He yawned as he turned away from the destruction in the forest, to a man with a green scarf and glasses.

"So what do yah want?" He asked as he flashed his patented grin. The man smiled in return.

"Sans Skeleton, I presume?" He asked.

"Yeah, that's me." Sans' hands were now in his coat pockets.

"I'll cut right to the chase; I'm Ozpin and I'd like for you to join my school. I am a headmaster for a school that trains its students to be Huntsmen and Huntresses."

Sans' eyes widened at that, and his grin even drooped a little in surprise. His lazy grin was soon back however as he said his piece.

"Why would I do that? I'm pretty sure you've noticed that I can do fine on my own." He said. Ozpin sipped from his coffee mug.

"Yes you are very capable, but I also see untapped potential in you." Ozpin started. "While my school trains students to handle Grimm, it also educates them, and helps them build relationships with others, much like how schools are supposed to. I'd hate to see the greatness you could become get wasted because of a missed opportunity." He finished as he took a long sip of his coffee to gauge Sans' reaction.

Sans' grin had shrunk in size "That sounds great n' all, but I've got jobs to do. Houses aren't free yah know? And I've never been too pressed about teams."

"Yes I'm aware. Luckily I've spoken with your bosses and they've given you permission to take a break from work. Besides, you'll be given a dorm room at Beacon anyway."

"You sure know how to sweet talk a guy don'cha?"

FLASH BACK END

'That was three days ago.' He thought to himself with a chuckle. He was currently leaned against the wall and looking out the window while listening to music. He was pretty content there and dozed off a bit.

A little while later the plane jolted as it landed, waking him up. He saw all of the other students leaving the flying vehicle so he figured it was time to go. He grabbed his one bag that he kept with him and strolled off of the bus leisurely. He wasn't sure where he was supposed to go, but he guessed he would get there eventually.

LINE BREAK

It had been 15 minutes since he started walking, and now he didn't know where he was. He probably should have followed someone else, but everybody was going in a different direction, so it was hard to tell which way was right. He stood still and tried to at least feel out the presence of others, but that was a difficult skill that he hadn't mastered yet.

Before he could try though a blond boy about the same height as him and a girl with a red hood ran up to him.

"Excuse me! Do you know where to find the assembly?!" The girl hurriedly asked. It seems they were in a rush.

"Nope, I'm lost too." Sans answered with his grin. The girl's head fell as she let out an exaggerated groan.

"Well since you're lost with us, you could help us look for somebody with directions. I'm Jaune Arc by the way, short and sweet, rolls off the tongue, and ladies love it." The blond boy introduced himself as they started walking.

"I'm sure they do."

"They do! Or at least, they will…"

"Well, I'm Sans Skeleton." Sans raised his arm to shake hands with Jaune and the boy complied. Once they clasped hands though, and obnoxious fart sounded. And Sans and the girl looked to Jaune accusingly, who blushed.

"W-wait I didn't…" He was cut off by laughter coming from Sans, who pulled a whoopee cushion from his jacket.

"Ah, the old whoopee cushion, never fails to make me laugh." Sans chuckled while the girl giggled, much to Jaune's chagrin.

"Aw, that wasn't cool." Jaune huffed and crossed his arms.

"No, but it was funny. I'm Ruby by the way." She giggled.

"It's nice to meet yah Ruby." Sans greeted.

"Say Sans what's your weapon?" Ruby asked after a while. "I've got this baby." She unveiled her Crescent Rose for the second time that day. Sans eyed the weapon with interest.

"That's a pretty nice tool for destruction yah have there. Is it heavy?" He asked.

"Nah, it's pretty light. So what's your weapon?" She asked again. Sans noticed that she seemed a little eager to see.

'Too bad she's gonna be disappointed.' Sans thought to himself.

"I don't have a weapon." He said lifting up his hands in the "what can you do?" gesture before putting them back in his pockets.

"WHAAAT? You don't have a weapon?! Why not?! Weapons are the culmination of our being. They are an extension of us!" She passionately explained. Sans eyes widened. He didn't think she'd be this much of a weapons nut.

"What? Are you saying that I need to extend myself? That I'm not good enough the way I am now? How dare you." Sans feigned offense to her words.

"Wait, no-that's not what I meant!" She sputtered as she tried to explain herself but stopped when she saw the boy grinning at her. She blushed and put her weapon away.

"Relax, I'm just yanking yer chain a little." He chuckled with Jaune joining him.

"Ugh, but seriously, why don't you have one?" She asked.

"I've never needed a weapon. I've handled everything just fine without one." He answered.

"Then, how do you fight?" Jaune asked. Sans paused for a moment before realizing something.

"Hey, that assembly thing is supposed to start soon, right?" They both took a moment to process this before yelling in shock.

"Oh no, we're gonna be late!" Ruby yelled as she and Jaune hurriedly ran to find directions.

Sans chuckled as he followed after them. If all the kids at Beacon were this interesting…

'I can tell I'm gonna have fun here.'

A/N: Done and done! So Sans has met Ruby and Jaune! It will only get more interesting from here!

Make sure to read and review, to tell me how you like the story! If it's terrible and you don't tell me, I can't fix it yah know?

Anyway, that's all for now!

Buh-Bye!