Hello there and welcome to the pilot chapter of my Highschool DxD/Undertale crossover. I came up with this idea the other day and just figured 'Heck I'll do a chapter and see what people think.' Depending on how well I do in this chapter, I may or may not write more of the story, but I'm probably going to, but who knows? And I may change one or two things in this chapter after it goes up, depending on the response to it.

Be sure to leave a review telling me what you thought so I can be filled with DETERMINATION to write more.

Disclaimer: I do not own Highschool DxD or Undertale

It was a peaceful morning in the town of Kuoh in Japan. The sun sat fully visible upon the horizon, the bottom of the round ball of fire just touching the curve of the earth. On this morning, birds were singing, flowers were blooming-

"SAAAAAAAAAAAANS!"

-And skeletons were screaming.

In one of the many houses within the town, a tall, possibly anatomically inaccurate skeleton who's skull was a more straight and geometrical shape than your standard skull, burst through the door leading to the kitchen and glanced around the house's living room, an angry look on his normally cheerful and smiling face. What was the cause of his anger?

The sock he was holding in his right hand.

Which had a large collection of stick-it notes™ pinned to it.

"What?" A short, big-boned skeleton wearing a blue hoodie, white t-shirt with black shorts and white slippers, who was sitting on the sofa and had turned his neck to the right to look at the other skeleton, asked with his usual perpetual grin present on his face, his hands shoved in his pockets.

"YOU KNOW "WHAT" BROTHER!" Papyrus roared. "THIS IS THE LAST TIME I AM PUTTING UP WITH YOU LEAVING YOUR SOCKS IN THE KITCHEN!"

"Jeez bro, aren't you being a bit loud? Maybe you should…" Sans closed his right eye. "… Put a sock in it?"

Papyrus' look of anger turned to one of frustration, his eyes nearly popping out of his skull, but a smile was on his face regardless.

"SAAAAAANS!" He roared, out of frustration over the bad pun.

"What? You're smiling." His older brother replied, his usual grin present, and Papyrus could tell it was filled with amusement.

"I KNOW AND I HATE IT!" Papyrus snapped back. He then noticed the offending article of clothing in his red gloved hand again and prepared to go off on another rant when a voice interrupted him.

"Papyrus… why are you shouting?" A quiet voice asked from the top of the staircase to the right of the kitchen door. Both of the skeleton brothers turned to look at the stairwell, a small, fairly pale skinned 15 year old boy was standing two-thirds of the way up, his straight medium length brown hair swaying from side to side, along with the short bangs on his forehead, as he rubbed sleep out of his eyes. He wore a striped blue and white shirt and black shorts. He lowered his arm and opened his eyes, which were two doe brown shining orbs filled with happiness and joy, which were both complimented by thick, dark brown eyebrows.

"OH SORRY FRISK! I DIDN'T MEAN TO WAKE YOU!" He said, after having released a scream so loud it nearly shattered the windows and probably woke everyone within a ten mile radius. "ITS JUST SANS CAN'T TAKE CARE OF HIS OWN CLOTHING. WOULD YOU BELIEVE I FOUND HIS SOCK IN THE FOOD MUSEUM? HOW DISGRACEFUL. THE FOOD MUSEUM IS FOR SPAGHETTI AND FOOD SANS, NOT CLOTHING!" The taller skeleton said, sounding offended whilst glaring at Sans, who just grinned back. Frisk smiled and chuckled.

"Yes, yes I would Papyrus." He said in a friendly voice. The young boy then looked at Sans and smiled again. "Good morning Sans."

"Morning Buddy. How'd ya sleep?" The short skeleton asked cheerfully.

"Great thanks!" Frisk responded cheerfully. "I'm really excited about school today!" He then blinked and seemed to remember something. "Hey Papyrus…" He turned to look at the taller skeleton. "…How do skeletons talk long distance?"

The other skeleton frowned. "HMM HOW DO THEY I WONDER…" The skeleton's frown deepened and he raised a hand to his chin, scratching it as he thought. Frisk just giggled.

"It's easy. They talk by tele-bone." The brown haired boy said, a smile on his face. Papyrus clenched his jaw and Sans barked out a laugh. He then gave Frisk a wink.

"Nice one kid. Although I honestly thought it was going tibia more humerus one than that." The short skeleton added. Papyrus looked positively nettled, but a grin was on his face nonetheless, despite his clenched jaw. He glanced at the clock on the wall and spun around to face Frisk.

"ENOUGH BOONDOGGLING AND TERRIBLE JOKES SANS, FRISK NEEDS TO GET TO SCHOOL." The taller skeleton turned and rushed back into the kitchen suddenly. "I'VE ALREADY PREPARED YOUR LUNCH FRISK! I'M SURE YOU'LL LOVE IT!" The skeleton declared as he charged out the kitchen with a lunch box. He placed it firmly in Frisk's hands and took a step back, a proud grin on his face. The human opened the box…

… To find it filled with spaghetti.

"YOU SHOULD FEEL HONOURED THAT I, THE GREAT PAPYRUS, DECIDED TO MAKE YOU LUNCH HUMAN! NYEH HEH HEH HEH HEH HEH!" Papyrus declared, flamboyantly placing a hand on his chest, or 'battle body' which was a white chest piece with gold trimming along the sides with an odd symbol on its left, and stood up straight. "NOW YOU MUST GET READY FOR SCHOOL. REMEMBER WHAT ASGORE'S CLONE TOLD YOU. YOU CAN'T BE LATE ON YOUR FIRST DAY."

Frisk smiled and closed the lunchbox. "Thanks Paps!" He said cheerfully, getting a grin from the taller skeleton.

"Maybe you should go to school bro. You could probably use it." Sans quirked, not meaning it in the slightest.

"ME? GO TO SCHOOL? I, THE GREAT PAPYRUS, DO NOT REQUIRE SCHOOL SANS! I AM ALREADY A GENIUS, AS I CAN CREATE THE MOST COMPLEX AND UNBEATABLE PUZZLES IMAGINABLE!" He paused for a few moments. "ALTHOUGH A SCHOOL THAT HELPS WITH JUNIOR JUMBLE WOULD BE GREAT…" The skeleton muttered silently, glancing sideways.

"Of course Paps. After all, you are…" Sans winked again. "… A bone-fied genius."

Papyrus's screams of torment could be heard from a mile away.

"See you later guys!" Frisk called as he ran off, now wearing the Kuoh school uniform.

"FAREWELL HUMAN AND GOOD LUCK!" Papyrus called out from the doorway.

"Have fun kid." Sans said with a wink.

"I will, and thanks guys!" Frisk replied. He then turned and picked up his pace, a smile spread across his features. 5 years had passed since that fateful day. The day Frisk had fallen into the underground and become involved in the struggles of the monsters. The day he'd met Flowey, Toriel and learnt of the existence of monsters. The day he had learnt about the power of his DETERMINATION and just what he could do with it.

The human child smiled as he thought of his first meeting with Sans and Papyrus, how he had solved the devilishly complex puzzles Papyrus had made, walked straight past the ones Sans had made, and then fought and then gone on a date with Papyrus.

What? There is absolutely NOTHING wrong with going on a date with a skeleton. Do you have a bone to pick about the issue?

Then he'd met Undyne, Alphys, Mettaton, and Asgore and managed to befriend all of them. He'd saved the underground, and possibly the whole world, twice, the first time from Flowey after he gained six human souls and tried to take over the timeline and kill Frisk over and over, and a second time when he defeated Asriel and saved the entire world from being endlessly reset.

His heart still constricted a little each time he thought of Asriel. Unfortunately, even with his SAVE power, he couldn't truly save the poor boy, as he had faded away shortly after destroying the barrier. Despite only having known the young goat for a few minutes (excluding the time he was trying to kill Frisk), Frisk thought of his as one of his closest friends.

If Frisk could, he would trade his powers of DETERMINATION just so that Asriel could live and see the human world, and spend time alongside the human.

Shaking his head, Frisk cleared the sombre thoughts from his mind as he ran through the streets of Kuoh, his school bag strapped to his back. He eventually reached the school, and stopped when he saw the large amount of people milling around outside. He hadn't been in a proper school like this before, yet despite it, wasn't the least bit nervous.

With a smile on his face and a spring in his step, he walked through the front gate. He quickly drew many looks, mainly from the girls, who started whispering about him.

"Who's that?"

"I don't know."

"His hair looks funny."

"He looks cute."

"You're right, he's such a cutie."

Frisk felt his cheeks heat up a bit and he scratched the back of his neck nervously. Despite having faced unimaginable horrors, the likes of which would leave most people scarred for life, and being able to walk away more or less unaffected, and saving the world on more than one occasion, he had no idea how to handle compliments.

"Aww he's blushing! So cute!" Several girls cooed. This attracted resentful glares from many of the male students, causing Frisk to feel extremely confused. Why are they looking at me like that!? H-Have I done something wrong? He wondered.

Shaking his head, the boy walked into the main school building, ignoring the looks from the other students, both male and female.

*Later*

"Class I would like you all to say hello to our newest class member Frisk-" The teacher quadruple checked to make sure it was the right surname. "-Papyrus."

Frisk, despite himself, giggled. Unfortunately Toriel hadn't been able to completely finish Frisk's enrolment papers before the trio had set off for Japan, and thus it had fallen to Papyrus to give Frisk a surname, as the human child had forgotten his previous one. Of course, being the skeleton he was, he used the name he thought the best for Frisk.

So of course he'd used his own name, because in his words "HOW COULD YOU EVER HOPE TO HAVE A BETTER LAST NAME THAN THE NAME OF I, THE GREAT PAPYRUS? I GRANT YOU PERMISSION TO USE IT HUMAN, BUT DO NOT TARNISH IT! NYEH HEH HEH HEH HEH!" Of course Papyrus didn't fully understand how last names worked, so Sans and Frisk hadn't really complained. He then realised Do Sans and Papyrus even have surnames?

"Pleasure to meet you all!" Frisk said to the class. He wasn't sure when it had happened, but not long after he and the monsters left the underground, he discovered he could understand and speak any language, regardless of whether or not he had heard of it before. He figured it probably had something to do with him being affected by the magic of the underground, but he didn't really know. Maybe I could ask Alphys about it, she might know.

Immediately after his introduction, whispers broke out across the class. This quickly caused Frisk to receive glares from many of the males, as the whispers were primarily compliments about how cute he looked.

The teacher coughed into her hand, indicating that it was time for the class to fall silent. "Excellent. Now… Frisk-san," The teacher wasn't sure whether or not to use his first or last name "Please take a seat. There is one open by Koneko-san."

Frisk's eyes wandered across the class until they came to rest on the white haired, hazel eye girl in question. Immediately he could tell she wasn't 100% human, a side effect of having spent so long around magical beings was that he could now tell if a being had magical power, and whilst Koneko's power had tinges of evil energy, he said nothing and smiled at the small girl. Her emotionless face gazed back, which was framed by two white locks of hair.

Her reaction, or rather lack of it, didn't faze Frisk at all. He walked over and plonked himself down on the seat to her right and withdrew his school books. "Pleasure to meet you Koneko-san." He said, extending a hand. He knew about the whole honorific thing with Japanese, and made sure to use it.

Koneko looked at his hand and then back at him. "Hi." She said, and took his hand. When their hands touched, for the briefest of moments, surprise and shock flashed across her face but she was quick to hide it. "Frisk-san." She said flatly.

Frisk nodded and let go of Koneko's hand, withdrawing his hand to his side. He then turned to face the front of the class, and prepared for his first school day with other humans. He couldn't wait to see what he could learn.

*Several hours later, end of school day*

Frisk stretched his arms above his head and yawned. His arms flopped to his sides as his yawn finished and he smiled. His first day of school had been great; he'd learnt so many new and exciting things that he couldn't wait to tell Sans and Papyrus about. Of course one or two lessons had been terrible, but he'd managed to make his way through them. Also Koneko had been giving him odd looks every now and then, but he hadn't said anything about it. He's gotten a few odd looks at lunch time when he'd pulled out a box full of spaghetti, but he'd gladly eaten all of it and more or less ignored the strange looks he'd been getting.

He got up and quickly packed his books into his bag and when he was done he slung it over his shoulder and made his way out the class. He blushed as several girls offered him compliment and one or two even asked him out. He politely declined and then ran off faster than when he was running away from monster fights.

He knew how to handle monsters. He knew how to handle evil flowers trying to take over the world. He knew how to handle spaghetti that had once been about as tasteful as dirt, he knew how to handle deadly fights for his life, he knew how to handle pun loving skeletons and he had the power to SAVE, LOAD and RESET anytime he felt particularly DETERMINED.

But girls?

Not the foggiest.

As he left the school, Koneko watched him from one of the many windows. When their hands had touched, she had felt a massive power inside of the young, cheerful boy. How she hadn't sensed it from a mile away was anyone's guess.

"I must tell Buchou about this at once." She said in her usual flat, emotionless voice, turning around and taking off down the corridor at the best pace she could manage. Although she seriously doubted Rias hadn't yet sensed the power of the young boy. But there was something else… something about the boy just seemed… odd. Frowning ever so slightly, Koneko pondered this as she moved through the hall ways of Kuoh academy.

Unawares to Koneko, both Sona and Rias had taken note of Frisk's odd power and were currently discussing it. "It's… different…" Sona said. "It doesn't feel like a sacred gear… yet it feels completely different from any other power I have ever sensed."

"Indeed…" Rias said, frowning slightly. "But he is cute… I must say."

"Do you believe he is a threat?" Sona asked, ignoring Rias's comment on Frisk's cuteness.

"I do not believe so. I cannot sense any kind of hostility from him. He will make a most interesting servant…" Rias said absentmindedly. Sona quirked an eyebrow at Rias ever so slightly.

"Don't you have a confirmed sacred gear holder to acquire first?" She asked. Rias blinked and nodded.

"Yes. But I plan to acquire Frisk as well."

"Do I not get a say?" Sona asked; a tinge of competitiveness in her tone. Rias caught on and smirked.

"I wasn't aware you wanted him Sona. If you want, we could settle it with a game."

Sona shook her head. "My peerage is already sufficiently filled. I have no need for him, I was simply…" Sona smirked ever so slightly. "… asking."

"Oh?" Rias asked. She then waved her arm dismissively and began walking off. "I must go. I'll speak to you later Sona."

"Very well, Rias."

*Several minutes later, elsewhere in Kuoh*

Frisk stopped outside the house that he, Sans and Papyrus shared. Ignoring the extremely out of place snow on the roof, which should've probably melted by now considering how long the house has been out of the underground, it was a nice, warm house. It had been modified by Papyrus to accommodate Frisk, mainly adding in a few doors and railing for the stair case and an extra room between Sans and Papyrus's rooms for Frisk.

Sans had originally been given the job, but after two months all he'd done was move the couch an inch to the left, and even that he claimed had been an accident.

Frisk walked in, a smile on his face. "I'm back guys!" he said cheerfully. The door to the kitchen flew open, revealing Papyrus wearing a pink apron which said "BEST CHEF" on the front in big bold words.

"AH! WELCOME HOME FRISK, I WAS JUST PREPARING DINNER. CAN YOU GUESS WHAT IT IS?" The skeleton asked. Frisk put a hand to his chin and frowned deeply.

"Hmm…" He then held his hands in the air. "Sorry, haven't got a clue." He admitted. Papyrus grinned.

"AH HA! ONCE MORE I OUTSMARTED YOU HUMAN! FOR TRULY I, THE GREAT PAPYRUS, AM THE MOST CUNNINGLY SCHEMING SKELETON THAT HAS EVER EXISTED TO OUTSMART A HUMAN SUCH AS YOURSELF! NYEH HEH HEH HEH HEH!" Papyrus declared cheerfully. "We have having none other than my soon-to-be-world-famous-but-not-quite-there-yet spaghetti! Nyeh heh heh!" And with that, the skeleton chef disappeared back into the kitchen.

"Sup." Sans said, appearing directly behind Frisk via use of his 'short cuts'. Despite it happening several times a week, Frisk still yelped in surprise and jumped across the room and landed flat on his arse, prompting Sans to chuckle. "Did I get ya'?"

Frisk smiled. "Yeah, yeah you did Sans." He got up and brushed himself off. The skeleton chuckled again.

"Glad to hear it. So how'd the first day of school go buddy?" Sans asked. He glanced at the sofa, and decided walking was too far, used a shortcut to move to his favourite spot on the sofa instantly.

"Great actually!" Frisk declared cheerfully. "There were lessons, and the teachers talked about all this cool stuff, and then there was this one girl who didn't feel like a human an-"

"Whoa whoa whoa ease up there Frisky, you're going a bit too fast. And what's that about a girl who didn't feel human?" Sans asked, the last part of his sentence far less cheerful than the rest. He leaned forwards slightly, and slowly reached for his magic. If there was someone in the school who wanted to lay a hand on Frisk, well, he'd show them what a bad time is.

"Oh yeah, there was this girl in my class. I looked at her and I could tell she wasn't human. She didn't feel like a monster, but she had magic. She felt like the Temmie's, but different. Like…" Frisk struggled to think of a comparison. "…Like… darker. Not all that dark… just like dark…" He wasn't the best at explaining these kinds of things. Sans frowned slightly, and made a quick decision.

"Hey kid, mind if I walk you to school tomorrow?" Sans asked. Frisk's eyes widened and he shook his head.

"No! In fact it'd be great if you could! I'd love to show you what my school is like. Hey, maybe you can join too!" Frisks brown eyes glimmered with joy. Sans chuckled.

"Nah kid, I got outta school a long time ago. Don't see a need to go back. Sorry pal, that's just the way it is." Sans said. Frisk's smile faded a bit, but then returned in full force.

"That's alright! I guess I can show you around then! I'm sure you'll think its cool!" Frisk said. "Not as cool as Papyrus though." He added as an afterthought. Sans nodded in agreement.

"Papyrus is the coolest." Sans said in agreement. A moment later Papyrus stuck his head through the kitchen door.

No, literally through the door. As in, it's still closed, but it has a hole the shape of Papyrus's skull in it.

"DINNER IS READY!" The skeleton declared. Sans and Frisk both grinned, Papyrus's spaghetti had actually gotten pretty good recently, and was nearing the delicious level of taste.

"Time to eat!"

"Welp, time for some grub. You got Ketchup?"

Papyrus rolled his eyes. "OF COURSE BROTHER. WE ALWAYS DO. TOO MUCH IN FACT..." He said exaspuratedly.

Sans' grin got wider. "Well what are we waiting for?"

And that's the pilot chapter done and done! Sorry if I rushed one or two things, but this is just like an intro chapter, and I mainly focused on getting the personalities of the characters right. Anyway, if you want to see more, or think I made a total screw up of this, please let me know, so I can write more/fix what I messed up. Yes Frisk is a guy, since I figured a girl wouldn't fit in well, and he's a kind, caring and kind innocent kinda person. As for the other characters from Undertale… well if the story continues they may or may not show up…

Adios!