Thanks to beta checker Latent Kindly, he's happy to help and looking for work.
"Italics"= thoughts/flashbacks
"Italics 'Italics' Italics"= thought within flashback
"Text" = Normal talking
Sans leapt back again as Undyne attacked with more spears.
"undyne! please stop!" He yelled at her.
'the hell is going on?!' Sans thought, panicked
"JUST FIGHT ME!" Undyne yelled, attacking again.
"why won't you stop!?" Sans yelled back desperately, diving behind a snow poff as another barrage of spears landed where he had been.
"IF YOU ATTACK ME I WILL! she yelled back, taking aim again.
"fine!" Sans yelled back, and readied an attack. Undyne stood her ground and looked at the snow poff, waiting for his attack; a single, small bone was tossed from behind the snow poff at her and then Sans' head poked up. The bone had made only half the distance to her before flopping weakly to the ground.
"will you stop now?" He asked her.
Undyne looked at him, then the bone incredulously. She then snarled and threw another barrage of spears at him.
"FIGHT ME PROPERLY! I KNOW YOU CAN!" Undyne yelled at him, rearing up to strike.
She was about to attack again when a loud cry caught their attention.
"NOOOOOOO!" The heartbroken voice echoed throughout the forest.
Undyne quickly broke off her attack and sprinted towards the noise, Sans trailing behind cautiously.
They turned the corner just in time to see the Demon farther down the path; finishing off the owner of the voice, a weeping Dogamy lying defeated next to a pile of dusty armour. Next to the Demon a little yellow flower was cheering and inciting them as Dogamy turned to dust. The deranged murders cheered for a bit longer before looking around, bored once more. Undyne quickly turned to Sans with a serious, yet urgent and demanding look on her face.
"Shit! Sans, no more pretending! We need to work together to kill that Demon!" Undyne yelled urgently at him. More people could be killed if she was not completely serious.
"what do you mean 'no more pretending'?" Sans asked her, seemingly confused.
'what is she...wait. she couldn't mean...' He thought.
"I saw you fight them before! In that stupid hallway! Fight them like you did then!" She yelled at him.
Sans' marrow ran cold. His eye lights turned out, and his tone went deadly serious.
"What did you just say? You saw me fight them?"
'she was dead by then. how could she see me fight the demon?! and how could she have remembered through the reset?!' Sans was confused and shocked.
Undyne was about to respond when she heard a scream. She turned and saw the Demon and Flowey attacking Monster Kid.
"NGHAAAA! LESS TALKING MORE FIGHTING! LET'S GO SANS MOVE IT, WE NEED TO SAVE THAT KID!"
The captain of the Royal Guard and the Judge ran towards the psychopaths. Undyne blocked the punch that the Demon had thrown at MK with a wall of spears then leapt in front of the kid, pushing him back to Sans.
"Don't worry kid, I'm here for you! Just stay back!" She yelled.
"heya kiddo, you hurt?" Sans asked MK with a worried frown.
"N-no, I-I'm okay." The scared MK stuttered. Sans' smile perked back up a little.
"good, that's good kid. now i need you to do something important. can you run?" he asked.
"Y-yeah, I can." Monster Kid stammered, getting up shakily.
"good, i need you to go back to town. warn everyone about the hostile human. tell as many people as you can on the way there as well, but don't take any detours. can you do that?"
"Yeah. I can do that."
"good, now go!" Sans commanded MK, who nodded; and, with a determined look, ran back towards town, only face planting once on the entire way there.
Meanwhile, the Demon was startled by Undyne's appearance, then they looked scared, before their grin returned, wider than ever. Flowey popped out of the ground behind Undyne and threw bullets at her, but Sans had turned back to the battle just in time to block the bullets with a spinning bone attack. The Demon blanched, before the sadistic smile returned full force. This was not only new and interesting; but it was going to be exciting as well.
"Oh Undyne, how on earth could Sansy help you?" The Demon taunted. Sans wasn't going to fight full force, not if he wanted to keep the resets a secret.
"Is that what you think?! I know he kicked your arse last time loser! C'mon Sans! LET'S KICK THEIR BUTTS! NGGGHHHHHAAAAAAAA!" Undyne yelled before screaming her battle cry as she charged up in front of them and engaged in a battle with the shocked maniacs.
'How does she know?!' They both thought.
"heh, no holding back this time i guess. time to make pap proud for once. i guess i'm ready. so let's do this undyne." Sans was quick to back Undyne up, walking up beside her with his hands in his pockets and his eye sockets shut before looking up with a grin on his skull as he entered the battle.
*Click, click, Beep!*
Sans and Undyne looked at each other before nodding. Undyne let forth a battle cry, not bothering to turn their souls green, before waving her summoned spear forth and sending an onslaught of spears towards the two lunatics coming from every direction. Sans watched her work for a few seconds, grinning while memorising her attack patterns, before his eye socket shone and he summoned an armada of blasters. Their charging whines ringing out as pure magic gathered in their maws. He used his immeasurable skill at judging an opponent's moves to expertly interlock his attacks with her own, creating a deadly maze of attacks. Undyne's fast paced and devastating spear attacks with Sans' ability to remove the temporary damage invincibility made for a fearsome combination. Adding in Sans' blasters, the Karmic Retribution effect, and the two maniacs' low LV meant that unless they were almost perfect with their dodging, their low health would quickly deplete to nothing; and they would lose.
No one was talking so the battle was mostly silent, with the occasional scream of pain or rage from the killers and Undyne's battle cry;, mixed in with the swishing of attacks and the whining charge up and deafening discharge of the blasters.
Every turn the two heroes would switch up their attacks, and Undyne would throw numerous spears that exploded into more spears, while Sans would smash massive and complex arrays of interlocked bones upon them like waves against a cliff. But unlike the cliff, the two psychopaths could dodge.
The Demon and Flowey were doing very well together, dodging nimbly. They also co-ordinated attacks; one would distract them and the other would rush in and attack. With Flowey able to slip into the ground and the Demon's large amount of practice with dodging; the two barely got hit, but when they did, it hurt bad. Sans however, was out-performing both of them, dodging or teleporting away from every single attack the lunatics had thrown his way while replying with more than a few counter attacks. Undyne just either blocked or took the attack head on, hitting them back twice as hard with her held spear when they got close. The battle seemed somewhat evenly matched. Then, Sans had a great idea, and decided to speak up in between the attacks.
"hey undyne! remember that movie we watched together for 'bonding time'? you know, the spartan one, 300. you get where i'm going with this?" He said to Undyne. Undyne looked puzzled for a second, before her sadistic grin returned wide enough to show every last one of her teeth.
"Fuhuhuhuh. That sounds dangerous, epic, fun, and awesome all at once. I LOVE IT! Just cover me for a turn so I can gather my magic for it!" She replied, standing back and began gathering her magic. Flowey and the Demon were baffled by their talking; but if Undyne was taking a break, they could attack Sans.
"right then. just us three for now. let's have some fun together. i got a skele'TON' more energy left yet. whaddya say? think you got the 'guts' to take me on or have i 'rattled' you already?" Sans winked at them and grinned wide as they groaned, before drawing together his determination; both eye sockets began blazing with bright blue and yellow energy.
Sans was able to keep the two on their toes as Undyne continued to gather her magic. He decided to forgo using blasters and instead attacked with almost a full graveyard's amount of bones. He also threw some rocks and branches at them with blue magic. Drawing on his natural determination he was able to keep his attacks going much longer than normal. But after a minute or two of constant attacking, he tired out, and the tsunami of bones trickled out into a stream before stopping completely. Flowey grinned manically and shot a pattern of bullets at Sans. He tried to block but one went through his defences and took off 8HP, the force sent him crashing to the ground on his back. Both maniacs grinned sadistically in triumph and Undyne gasped in shock and ran to go help him, but she stopped when he shakily raised his hand and gave a thumbs up.
"i'm okay! i'm okay! heh, thank god for the HP rise i got this morning; but, uh — you ready yet, undyne? i don't think i can keep these kids entertained much longer. i'm just about 'sans' magic right now, heh." He said. He slowly and shakily stood up, gasping for breath. His bones were screaming for rest — his body and clothes soaked in sweat.
"YUP! You rest this turn, I got this!" Undyne yelled, feeling almost as good as she did when she started, and this time bursting with magic.
The psychopaths took their turn to heal their low HP before Undyne grinned sadistically at them. Sans grinned weakly at them too, before slowly limping back and sitting against a tree, Sans took a ketchup bottle out of his hoodie, popped the top off and took a swig. Thanks to the healing powers of monster food he felt better almost immediately. He leaned back on the tree with a grin and gave Undyne a thumbs up. She grinned in response, before turning back to the killers. This was going to be fun to watch.
"ARE YOU READY FOR THIS?! TIME TO BLOCK OUT THE SUN WITH MY SPEARS! FUHUHUHUHUH!" She yelled, before cackling madly as she raised her arms and enough magic spears to equip an insurmountable army rose up from behind her. She swept her arms forward and the tens of thousands of glowing spears shot up into the sky, before raining down upon the maniacs. The dust covered lunatics were forced to sprint and dig madly back towards the ruins, HP dropping drastically as the spears rained down upon them like a monsoon. Undyne watched them run into the ruin's door, before the bridge leading to the door was collapsed and broken by the rain of spears.
"THAT'S RIGHT! RUN YOU COWARDS, RUN! FUHUHUHUHUHU!" Undyne yelled at them, before turning back towards Sans, who had collapsed to the ground and was holding his 'stomach' as he laughed. Undyne smirked again, before holding a hand out for him.
"heheh, t-thanks undyne. that flower really wanted to 'leaf' quick. they must really be 'fishing' they didn't cross us today, huh? heh." Sans choked out between fits of laughter, taking her hand. Undyne pulled him back to his feet and they both composed themselves while brushing the snow off their clothes. They then turned to each other and fist bumped, both grinning madly.
"It's no prob Sans. I thought fighting against you was going to be fun but fighting with you was AWESOME! Alphys really needs to hear about this!" She exclaimed as she dispelled the spears.
"heh, well knowing her, she probably watched and recorded the whole thing. but, i think we need to have a chat before you go and give a play-by-play while you watch it with her." Sans said.
"Yeah, we probably do, don't we." Undyne replied sheepishly. Sans' tone got serious and his grin disappeared.
"What did you mean when you said you 'saw me fight them before'? Please explain to me." Sans asked. Undyne scratched the back of her head and smiled awkwardly. This was probably going to take a while to explain...