Author's Notes: I was thinking of an Undertale crossover, the setup for the crossover seemed to come naturally, deciding with which other franchise was the hard part. I'm reasonably happy with the setup, if you have anything to add please feel drew to review or PM. If you enjoy it please favourite/follow/review. If people enjoy I'll continue. Hope you enjoy, any thoughts please let me know.

"It's a beautiful day outside. Birds are singing, flowers are blooming. On days like this...kids like you...SHOULD BE BURNING IN HELL." The normally impassive Sans was filled with rage and with Determination, as Frisk advanced upon him her eyes wide and bloodshot, droll dripping down her chin, her bloodstained hands desperately holding onto her often used knife. Taking a deep breath, Sans readied himself as Frisk charged, his eye shone blue as he unleashed his trump card, his strongest attack, telekinetically slamming the murderous child against the floor and the walls of the Judgment Hall, each impact hard enough to chip stone and leave craters in it's wake. He unleashed a barrage of faster blasters, many of which were dodged, a few however hit their mark. A reign of bones fell upon Frisk's prone body, the child remained silent, not even crying out once in pain despite the multitude of broken bones and scorched flesh.

"Huh. I always wondered why people never use their strongest attack first." Sans advanced upon the barely conscious Frisk, who swung widly up at him, each blow Sans contemptuously dodged. "This is for my brother." His voice little more than a whisper as he fired a faster blaster point blank into the face of a small child. The smell of burning flesh almost made him sick. "That was one. How many times will I kill her, this time?" He wondered aloud, as the timeline reversed once again.

"Heya, you look pretty frustrated about something, guess I'm pretty good at my job,huh?" Unsurprisingly the question was not answered, the monster he faced had devolved so greatly, he doubted it was capable of human speech. This time Frisk was able to react slightly better to Sans' opening salvo, though heavily injured the child could stand, limping she swung her blade aiming for Sans' throat, which he easily sidestepped, his eye shining blue, Frisk was repeatedly slammed against the floor, until all signs of struggle stopped.

The cycle repeated dozens of times, each time Frisk would inch closer to wounding Sans, she would avoid more of his attacks, fatiguing the weary prankster. Sans stood there, eyeing her wearily from across the room, his eyes desperate to close, his breaths shallow and ragged, he was no longer able to work out how many times this battle had been fought, only that he had won numerous times, yet this monster before him would not give in, steeling himself for his next attack, he watched the injured creature do something totally unexpected, it spoke. The voice was a garbled, twisted static, the volume waxing and waning, the sound of its speech physically pained Sans, it was like a white hot spike being pushed into his cerebral cortex.

"I will show you...mercy...Sans...we are friends after all. I will spare you...just let me pass."

"You're sparing me? Finally, buddy, pal. I Aknow how hard it must be... to make that choice. To go back on everything you've worked up to. I want you to know... I won't let it go to waste...c'mere, pal." Frisk inched closer to Sans, attempting a friendly smile, which to Sans was little more than a malicious sneer, "Drop the knife." Sans commanded, the creature hesitated for a moment before dropping the bloodied knife at her feet. Sans waited for her to come closer, eyeing every inch, when she was within arm's reach, his eye shown, it was enough to scare even a craven monster such as Frisk. Sans summoned his faster blasters above her head, and shouted for the first time in their confrontation.

"GET DUNKED ON." As he watched the life drain from her eyes, Sans spoke his voice quiet once more, full of sorrow and regret. "If we're really friends you won't come back." As Frisk lay there dead, Sans stood there waiting for the inevitable for this battle to resume once more, he spoke to the corpse. "You didn't spare my brother."

The battle raged on once more, Sans was losing his Determination, the futility of his situation becoming ever more apparent, Frisk could sense her opponent weakening. Soon Sans was hard pressed to do more than defend, a wild swing of her blade sliced open the fabric of Sans' blue jacket exposing a section of his skeletal frame, Frisk grinned maniacally sensing victory was close at hand, Sans desperate attacked injuring his foe greviously, alas it was not enough; with a startling display of speed, that Sans weary in both body and soul, was simply too tired to avoid, Frisk thrust the knife into his body, white hot searing pain brought him to his knees as the blade was ripped out opening a wide gash on his chest, blood slowly leaked from the mortal wound. Sand eyes both blue and gold flared into life before dimming to a pale mockery of their usual vibrance, forcing himself to stand he walked away on unsteady legs, his vision blurred, he spoke his final words, as Frisk walked past him, no longer interested in her fallen for.

"So... guess that's it, huh? Just... don't say I didn't warn you. I'm going to grillby's Papyrus, do you want anything?"

He awoke in his bed, the room dark, the gentle sounds of the town outside reverberating through his open window, his head hurt, it was as if he was trying to remember something important but the memory escaped him. He lay in the darkness staring at the ceiling, letting his mind wander, hoping for an answer, eventually it came. Fragmented memories, Papyrus's corpse, his countless battles in the hall of judgment, even his own death. Something within him had changed, he had never seen the past timeline before so clearly, throwing the blanket off of himself and into the ever circling trash tornado, he made his way down into the basement, what had once been his lab, before apathy and sloth has crippled him. He would not let the cycle repeat. He would not watch his brother die again.

Sans was filled with Determination.

Throughout the night and long into the next day Sans worked without stopping, running countless scenarios through the computer, a blackboard full of equations scrawled haphazardly across it, papers strewn across the floor. Sans was growing frustrated, he knew it was possible, he knew there was a way to remove himself and Papyrus from this world of repeating timeline, from an oroborous of death and rebirth. Hours passed as Sans worked tirelessly, as the sun was setting he was interrupted from his work by a knocking on the door, turning his face to the source of the sound, he could see his brother walking into the room, holding a covered plate proudly before him.

"Brother I see you have not eaten yet today, and I The Great Papyrus have come to your rescue with my, wait for it." He ripped the cover from the plate to proudly unveil a large serving of spaghetti. "My famous spaghetti, nyahaha."

Sans cracked a smile, the most relaxed he had felt since waking last night. "I'd sure regretti if I didn't eat your spaghetti." He punned with a wink, appalled Papyrus responded.

"Brother! Spaghetti is a serious matter, it is not for making jokes. My famous spaghetti is no laughing matter...nyahaha."

Sans suddenly serious turned to his brother. "Y'know Papyrus, you're the best brother a guy could ask for, even if you pain me down to my bones at times."

"Brother you're so silly, it's a good thing you have a cool guy like me to look after you."

Sans voice was tinged with a sadness, Papyrus had never before. "That's right Papyrus, you do look after me..."

Papyrus confused looked at his brother. "Brother I'll leave your spaghetti here, I hope you enjoy it. I'll be upstairs if you need me." Sans watched his brother go with a heavy heart, visions of the fate that would befall his brother if he did not succeed.

"This time Papyrus, I will protect you." Turning his head to the plate of spaghetti sitting on his desk, he continued. "But I will not eat that. No matter how much ketchup I put on it."

For days Sans toiled away ceaselessly, not eating, not even sleeping which was an oddity for the languorous skeleton, until at last a breakthrough.

"I've done it...well I think I have. Guess we'll just need to wait and see..." His words trailed off, as sleep finally took him. He was finally roused by Papyrus making his way into the room, Sans was slumped over at ha desk, his eyelids fluttering open as his brother stepped closer. "Brother you are starting to worry me, you've not left the basement in more than a week, all the spaghetti I've brought you is starting to smell."

"Sorry Papyrus I've had a lot to do." His brother explained to the worried skeleton. "That should be me more or less done, I'll have more time to spend with you, I just hope you've not got a bone to pick with me because of all this."

"Brother!" Papyrus whined, "Please stop with all these skeletal puns!" Sans forced himself to stand, his body still fatigued from the lack of sleep; he surveyed his experiment, his latest invention. It was a rather unassuming device ark of metal less than a metre in size, a complex array of wires and circuitry ran into a keypad with an LED display. If it worked as he hoped, he would be able to program in the coordinates to another reality, hopefully one of those realities would be a haven for him and his brother, a world without the unending cycle of death and rebirth. Papyrus made his way over to his brother and the strange device before him. "What's so special about this strange device, does it make spaghetti?" Papyrus reached out to touch his brothers invention and before Sans could stob him, gloved fingers impacted with the sensitive keypad of the device.

"Oh boy we're gonna have a bad time..." Sans quipped before the world flashed before his eyes, blue to black to white, pain lanced behind his eyes and he slipped out of consciousness and into oblivion.

The slums of Midgar, smog hung heavy in the air, the dull glow of neon lighting illuminated the labyrinth the interconnecting alleys, side streets all leading into the main streets, roads wide enough for militarised vehicles to easily pass. Street gangs and the Shinra militarised security forces both prowled the streets and preyed on those civilians incapable of fending of the reavers. Aerith was something of an oddity in this regard, the soft spoken delicate featured young woman, stood out amongst the din, both for her good looks and her gentle attitude, normally a lone woman such as herself would be an easy target for the degenerates who roamed the back alleys, she however despite appearances was more than capable of defending herself. A basket of flowers in her hands, she stood on a street corner, whistling a merry tune, bouncing on her heels and watching the faces of those passing by. She smiled at everyone who caught her eye, striking up casual conversation with a few civilians, she even managed to sell a few flowers, until someone caught her eye, a blonde haired man. Broad shouldered but lean, his blond hair spiked upright, bangs framing feminine but strong features, it was his eyes that truly stood out to her though. Blue. Piercing blue eyes, unlike any she had ever seen before, they seemed to almost glow against the illumination of the street lamps. Slung across his shoulder was the largest sword she had ever seen, as large as a man and almost as wide, a single edged monstrosity too heavy for most to lift, far too unwieldy for a normal human to wield in battle. Stepping in front of him she beamed her warmest smile. "This is for you." She offered him a yellow flower from the basket she held in her hands, the man stood there expressionless, merely looking at her without speaking. "Are you okay?" She continued, a little concerned and unnerved by his odd behaviour. After a few seconds of silence the man finally responded, his voice calm and collected.

"A flower?" He asked his voice betraying the faintest hint of confusion, she nodded vigorously, her smile never once dimming.

The man questioned this, "Why?"

"It's a gift." She answered as if it was the most obvious thing in the world. "You looked like you needed a pick me up."

The man sighed in resignation. "Fine. How much?"

"Well that depends, the price varies from customer to customer, for you...it's on the house." Handing the flower over, she felt a surge of electricity as their fingers touched. "Take care, Mr. I hope your girlfriend like it." She watched as he walked away, holding the flower delicately in calloused hands, after a few steps she heard him mutter under his breath.

"I don't have a girlfriend." She didn't know why but those words sent a flush to her cheeks, and set her heart a flutter.

"We'll meet again, Mr Swordsman. I have a good feeling about you."

Sans awoke on a bed of flowers, each slight twitch of his small frame led to a gentle caress of flowers against his skull. His eyes opened to a an empty building, one he had never seen before, the roof was half rotted, sunlight streamed down onto his face from the holes that peppered it's span. He was drowsy, his head felt heavy, his vision swam; he did not have the strength to rise, all he could do was look around at his surroundings, he was in a church, one long abandoned, wold flowers grew from beneath the cracked and broken floorboards, moss and ivy grew up the walls and covered the few pews that were still whole. Slowly the church doors swung open, Sans tried to push himself upright, however his strength had not yet returned, all he could do was watch as a a girl wearing a simple pink dress made her ways towards him. A human. He had little experience with humans and almost all of those were bad. Her face twisted momentarily into shock before resuming a neutral expression, she stopped a few feet from him, studying him before she began to speak. "Hey, are you okay...whatever you are?" Sans was taken aback, she did not seem overly fearful, rather she was enquiring after his wellbeing. His eyes met hers, bright green orbs that dominated a gentle face, something about them soothed his soul.

"Sans. I'm Sans, Sans the skeleton." The woman reached out a gentle hand, soft skin against hard bone, she helped him stand.

With a smile she introduced herself. "My name is Aerith. Aerith Gainsborough. I'm a human."

Sans just now fully coming to his senses looked around his surrounding once again, screaming out in panic, his voice desperate. "Papyrus! Brother! Brother, where are you..." The volume in his voice faded to little more than a pained whimper, which stung at Aerith's heart.

"What happened, Sans?"

"I...I don't know. Me and my brother we were together and then..I woke up here, I don't know where he's gone...he wouldn't leave me..." Aerith wrapped her arms around the diminutive skeleton, his body trembling against hers; in all the timelines in which he had existed, no matter the tragedies that had befallen him, Sans had never felt so totally and utterly without hope.

"It's okay, it's okay." She murmured soothingly, "If he's turned up anywhere near here, someone will know. I'm sure we'll find your brother, Mr Skeleton." She laced her fingers between his once again and began to lead him away. "I'll take you to my home, and we'll find your brother, okay." Sans wordlessly followed after, his mind racing.