AN: So this has been an idea stuck in my head for a while, just a stupid AU where battles in Undertale are done using duel monsters and duel disks that form from their soul, similar to the solid light vision of Arc V, with everyone's deck reflecting them in some way.
As for this fic really more of a proof of concept of how it would work and really just to get me to do writing, might be a one shot, might do more what if duels and concepts if people want more.
Other AU Information, this AU is pretty much the same outside of how battle is done but I could see in theory AU mix ups like Swap, Fell, etc working just change character personality and deck style.
It was a good day in Hotland for our favorite pun spouting skeleton, he got a great nap in and sold 3 hotdogs and a hotcat. Pretty good day, least till he heard the sound of armored boots coming towards him. He opened one eye socket and could see he and his brother's boss Undyne walking over to him, not looking pleased.
"Morning Boss, care for a hotdog?" he asked in his usual snarky tone.
"San's it's 4 in the afternoon, and you haven't been on patrol according to your brother for 3 weeks," she said clearly trying not to snap at him.
"On my break," he said, shrugging his shoulders in his usual casual way.
Everyone in the area could hear a loud crash of wood splintering under her fist that she used to hammer down on the now broken stand.
Without missing a beat Sans then said, "So gonna assume ya don't want a hotdog."
Undyne glared at Sans and shouted, "You never take things seriously, honestly I only put up with you because your brother does your share of the work!"
"Hey I get a lot done, a skele-ton," he said chuckling.
"GRRR YOU IDIOT!" she cried as her own soul disk appearing on her right arm, straight in the shape of a blue spear.
"What's all the noise?"
The duo looked to their side and could see a duo of Papyrus and Frisk walking over. A paper bag of sweet and Temmie Flakes being held by each of them.
"Hey bro, Frisk, doing work for Alphys again?" Sans asked, ignoring the angry fishwoman.
"Uh huh, she wanted more sweets." Frisk quietly said, almost in a whisper.
"And the great and helpful Papyrus would be dishonored if he didn't at least offer to help my good friend carry the groceries," Papyrus said in his overly dramatic tone.
"Grr Papyrus your brother hasn't been on his patrols for weeks, and it's clear he doesn't seem to care about his job, look I need to be the bad guy here and say if he doesn't straighten up I'm gonna have to kick him out of the guards," Undyne explained.
"Eh fine, I quit, I'll take my severance pay," Sans said, "Gotta catch up on my cat napping, thinking I'll visit the Temmies."
Undyne picked him up by his hoodie and looked him straight in the eye socket, "oh no you don't I'm gonna take you down right now...gonna show you why I'm in charge, you don't get to leave unless I say so" she said.
"So a fight ya want, alright, so where ya wanna do it?" he asked, being pretty chill all things considered.
"Did I hear you say fight?" a robotic voice called out and from above landed the brick shaped robot itself Mettaton.
"Where did you come from?" Undyne asked somewhat taken aback by this sudden celebrity cameo.
"Darling I'm like a superhero, I know when I am needed, and you need a venue for a fight, I suggest my own studio, with lights, camera, drama, so much for the monsters of the underground to see," he said, Frisk could see twinkles in his screen as he spoke.
"Eh I don't know, wouldn't want to embarrass the captain of the guards-" Sans said shrugging his shoulders while being held by Undyne
There was an audible neck snap as her head turned to face San's.
"Oh that's it, you and me out live, I'm gonna show you why I'm in charge and then you are out of here!" Undyne cried out.
"This can only end badly," Papyrus said and Frisk murmured in agreement.
A few hours later the stage was set for the duel, as the executive producer, writer, showrunner, star, sound and editing, Mettaton easily pulled the strings for this improtue live battle between guard and captain, also hooked his personal friends up with front row seating in the audience.
Frisk and Papyrus were munching on some popcorn, Lady Toriel and King Asgore, sitting on each side of the human and skeleton each had their own tea and biscuits set. Alphys sat to the left of Toriel munching on some sweets, excited to see Undyne kick some ass.
From the stage came the robot entertainer himself, in his more stylish humanoid form he drew out a microphone from inside his chassis and called out.
"HELLO OUT THERE UNDERGROUND ARE YOU READY FOR SOME DRAMA ON THE STAGE!"
He paused to hear the crowds call out
"YES METTATON!"
"Good to hear!" he called out laughing a bit, clearly he was excited, "Our duelists today will be the one and only Undyne, the great captain of the guards who I heard suplexes boulders for fun in her spare time.
Undyne stood firm and waved to the crowd, a confident smirk on her face as she formed her soul disk.
Mettaton then turned his attention to the hoodie wearing skeleton who was just standing there with his hands in his hoodie's pockets.
"And of course who could forget our pun loving skeleton Sans, who I heard once slept for 2 weeks straight!" Mettaton called out, San's just gave a weak wave to everyone, his eyes closed like he was tired.
Papyrus called out, "IT'S TRUE I SAW IT!"
Frisk smiled but was concerned, and what Mettaton explained gave reason as to why.
"Now then to those of you at home who never had the chance to duel allow me to explain some things, here in the underground your soul is your life, so the stronger your soul the more lifepoints you start with, of course weaker souls go first, gotta make it a bit fair after all. Also while these fights can be a bit dangerous, we at MTT would like to remind you that unless it's life and death there is no reason to try and bring harm onto our fellow monsters, oh and human friends of course," he said referring to Frisk of course.
Frisk gave Mettaton a wave and smile and the robotic host waved back.
"So duelists bring out your soul disks and we will see some actions!"
Sans then said, "Well if I must" before his own soul disk appeared by his left arm, a white bone. However now that both were out and ready to face each other, numbers appeared over each person's head. Undyne had 4000 while Sans had 100?
There was a bit of a stunned silence by everyone, including Mettaton when they saw that.
"What, big things come in small packages don't you know?" San's asked , shrugging his shoulders, their decks appearing over where their hearts would be, ready to be drawn.
"Duel!" Both called out and San's looked at his 5 cards.
"Well guess I don't have much to work with, I'll lay three cards face down and then summon skull servant in...eh doesn't matter, attack mode," he said almost bored, "Turn end"
Everyone's jaw dropped, except Papyrus, all at this move.
Skull servant put up it's dukes and looked ready to fight, despite only being at 300 attack and 200 defense.
Undyne was flabbergasted by this, both that foolish move and the robed skeleton trying to intimidate her.
"I'm sorry did you say attack mode?" Mettaton asked, putting the mic to San's face.
"Like I said doesn't matter, my traps will keep me safe," he said.
"Uh, you know you don't have to say a facedown card has to be a trap right?" Mettaton asked while the audience laughed, San's was clearly an amateur.
Frisk looked to Papyrus concerned, he knew San's had a weak soul but he wasn't playing smart.
"Don't worry Frisk, he knows what he is doing, he may not look like it but he is," Papyrus said, his tone a little more serious.
"How so?" Frisk asked, confused by Papyrus's more serious tone.
"Because I've never beaten him before, and I'm the great and powerful Papyrus," he justified.
Undyne drew her card and pointed at him, "Ok that's it, I'm gonna show you what happens when you mock me like this!"
She played a spell, "I activate the field spell A Legendary Ocean!" she called out and from around them the field began to change into a backdrop of Atlantis, fish seemed to swim around them in the air, some around the audience.
"With this spell I reduce the level of all water type monsters in my hand and field, like this one, the Legendary Fisherman!"
Appearing was a powerful shark rider however this one seemed to look more like Undyne's species of fish person, albeit more scarred and male. The rider twirled a hunting harpoon and smirked at the robed skeleton.
(1850/1600, level 4)
"Best part about him, while Umi is on the field he gains immunity to all spells, sure it includes my Ocean as well which counts as Umi but that means you can't touch him with your spells." she said pointing at him.
"I set traps," Sans said in his usual snarky tone, "pay attention."
Undyne growled at him and then played a new spell
"I activate Legendary Hunter" she said, playing a spell that looked like the Legendary fisherman aiming his harpoon at Fortress Whale who was aiming a cannon down at him.
"While this spell is on the field, if my fisherman attacks, none of your traps can affect him, no destruction, no negation. You basically can't do a thing to stop me, Fisherman show him who's the top predator in the ocean!"
The fisherman gave a cry of battle and charged forward on his shark and threw the harpoon right into the skeleton who disappeared into dust, however…
"I activate my trap, Will of the Normal!" he called out his trap that had the image of a group composing of a Skull Servant, Ojama Yellow, Mokey Mokey, Volcanic Rat and Charcoal Inpachi facing down a Dark Ruler Ha Des.
"With this continuous trap I take no effect damage if I have a level 2 or lower normal monster on the field, nor do I take battle damage in battles involving them," he said, his tone while calm had a sense of weight to it.
"There is more, you triggered two more traps, Human Wave Tactics, and Charge of the Normal!"
The Charge of the Normal shows a large army of different colored Ojamas charging into a warrior type monster's camp, one of which is a very confused Marauding Captain who was trying to get his armor on.
"So let me explain why you screwed up," he said giving her a smirk, "With Human Wave Tactics I get to special summon from my deck a level 2 or normal monster to replace any that were destroyed in battle on the field." he said, "course end of the turn, but with Charge of the Normal, well whenever I special summon a level 2 or under normal monster I return a card on your side of the field back to the hand," he explained.
Undyne began to sweat, she walked right into this trap hook line and sinker.
"You…" he swallowed a bit and calmed down, "alright then, good move, I set one card face down and end my turn," she said trying not to show face to Sans or the audience.
"Good then at the end of my turn I special summon another skull servant in attack mode!" Sans declared as suddenly there was a rumble under the ground where the fisherman was hovering.
"With Charge of the Normal I choose to return your Legendary Fisherman back to your hand," he said and with those words from the ground came shooting up the skeleton, pulling off a pretty good maneuver as he upper cut the fisherman, his eyes sockets glowing gold as the monster turned back into a card returning to Undyne's Hand.
She grimaced as her legendary hunt spell shattered into nothing, "Without my fisherman my spell can't remain on the field," She said face palming, muttering something about losing to this dweeb.
Frisk looked to Papyrus, "Wow your brother is pretty good."
"He is, if he wasn't so lazy he might be even better but it can be scary sometimes when he duels, don't know where he gets it," Papyrus said munching on some popcorn, getting tomato sauce on his teeth.
Asgore muttered a bit, "I've dueled Undyne before in practice rounds, she is a tough opponent, but I think San's has the advantage because she expects a more offensive style of dueling, she isn't too used to overly defensive tactics," he said nodding his head.
"So how many times has she beat you?" Toriel asked, raising an eyebrow.
"Uh, well, err," He rubbed his cheek with his index finger not willing to speak up about that.
"Come on Azzy," She said smirking, "Can't be as bad as our win lose ratio."
"...24 wins, 1 loss," he said downtrodden.
Toriel snorted a bit before turning her attention back to the duel, Frisk patting the saddened king on the shoulder.
"Finished with the peanut gallery?" Sans asked, drawing his next card, "Cause I love a good commentary much as the next guy but ever noticed how it seems to slow the duels down, or that just me?"
He looked at his next card, "Hmm alright then I summon Hinotama soul (600/500), " he said, summoning the floating fireball with a face, it looked to Undyne ready to strike her.
"Both of you attack!" he declared with both of them charging at her, but she flipped her trap.
"Don't think I'm that easy to take down," She said revealing wall of disruption.
"With this trap for every monster on your field they all lose 800 attack if they are in attack mode," she explained batting the two weak monsters away.
"Think I'm gonna let some scrub like you do damage to me, don't even think I'm gonna let even one life point taken down by you!" she cried out angry at him, Sans just smirked.
"You know you wasted a trap early on, should have saved it for the end," He said.
"Screw you bonehead," she said draw and then resummoning the Fisherman.
"I end my turn, not gonna let you special summon any more monsters," she said trying to calm down.
"Then back to me," Sans said looking at his next card, "Hmm well I guess I should just lay this face down and end my turn, not like I can attack, but hey neither can you," he said keeping his chill grin.
Undyne drew and then saw the card, "Perfect," she said seeing it, "I play the spell Heavy Storm!"
"Oh My, she played a very powerful card, I hope the studio can handle this, otherwise Burgerpants is gonna have quite the mess to clean up!" Mettaton called out as winds began to pick up around both duelists.
"Thats right, with this spell all spells and traps on the field get wiped out, meaning you won't have any defenses to play!" Undyne declared laughing at Sans who kept his calm as his cards began to quiver and everyone of the spells and traps shattered in a cloud of smoke.
"Fisherman attack!" she called out but the fisherman didn't seem to move, he was looking around as if he couldn't hear her.
"You hear me? Attack!" she repeated but as the dust cleared San's left eye was glowing blue and a trap was on the field still, it looked like a Skull Servant standing alone in a graveyard, his look stoic as he faced the viewer.
"The reason he won't attack is because with my trap Anger of the Normal when it was sent to the graveyard thanks to your card, not only do I get to add a level two and under normal monster, but you can't declare an attack, plus your monsters on the field lose attack equal to the original attack of a normal monster I can send to the graveyard, like my Hinotama soul," he explained as the monster disappeared and the fisherman groaned clutching his heart as his attack went from 1850 to 1250.
"Fine, doesn't matter, I end my turn with one facedown card, not like you can pull a win from this with nothing but weak cards," she said gritting her teeth.
"You know Undyne you underestimate me, all this time you think I'm just some weak monster, fine maybe it's true but there is more to me and my deck then meets the eye," he said while drawing his card, he smirked and said, "I play monster reborn to bring back skull servant."
From the ground appeared the original skull servant who glared at Undyne.
"Then I play my third one," he said, summoning the last one.
"What can you do with three skull servant-wait!" her eyes went wide as dinner plates, he had 3 level 1 monsters on the field.
"Now you get it, yeah I may have a weak soul, but even I can do a lot of damage if I put my mind to it," he said his eye still glowing blue, "I overlay all three of my skull servants to build the overlay network!" he declared as the three monsters were sucked into the vortex in the ground.
"From weakness comes strength, from this strength we are ready to dish out true karma, Rise up Lord of the Skull Servants!" he declared loudly as a large skeleton in a similar robe to the original skull servant, however it looked much darker and it was tattered, the face of the monster had multiple scars and cracks like it had been through hell and back. (?/?)
"No way...he can xyz summon?" Undyne said a bit worried now, more so she never even heard of this monster before.
"My monster gains 1000 attack and defense for every overlay unit on it," San's explained, "And if all the overlay units on my monster are skull servants, while on the field I can negate the activation of a trap you trigger once per turn," he explained giving her a smirk.
"No way, my trap," she said now sweating profusely as she looked at her trap, Sea Stealth Attack, if she triggered it, he could negate it, she looked up to the monster who was cracking it's knuckles, ready to face down the fisherman.
"Lord, attack her fisherman!" he ordered and the lord jumped into the air drawing a rapier from under it's cloak and thrust it into the fisherman's chest destroying him by shattering.
Undye Lifepoints: 4000 to 2750
"Alright, not gonna lie, good move," she said while clutching her shoulder, that attack, felt a lot stronger than even Papyrus...no even King Asgore when she dueled them, what kind of power was he hiding?
"I agree Sans that was quite the impressive maneuver and with a 3000 attack point monster Undyne will have trouble trying to take that monster down," Mettaton said but Papyrus then spoke up, "It's not over yet,"
Everyone looked to him in the audience confused but Sans gave a chuckle, "My bro's right, sorry Undyne but it's over for you, I win."
He pointed to his monster, "By removing one overlay unit, my monster can attack again...meaning I can do this two times and you lose," he said removing one unit.
"No way!" she cried out as the lord now at 2000 attack struck her dead on with his rapier sending her back a foot from the impact
Undyne Lifepoints: 2750 to 750
"And now the final overlay unit," Sans said, "Finish her!"
It nodded it's head to him and once again struck her in the chest with the blade, sending her flying back into the studio wall, somehow Sans had won…
The audience was silent, the images had disappeare and they could see Undyne groaning, having pulled herself out of the rubble.
"No freakin way, you, not only beat me, but you...did it with such low life?" she groaned dusting herself off as she went back on stage.
"I agree, I've never seen such impressive dueling, least not without looking into a mirror." Mettaton said before letting out his trademarked laugh, "Tell us Sans what is your secret?"
"My secret, well I don't have a secret, I just do what I can, "Sans said shrugging his shoulders, "So can we hurry this up, I'm missing out on some good nap times."
Undyne was about to yell at him but she took a deep breath, "Alright I won't deny you beat me, so guess you can just walk out of the guards," she said hating to admit defeat.
"Naw I think I'll stay, someone has to keep my brother out of trouble," Sans said, but not before Papyrus yelled, "YOU ARE ONE TO TALK BROTHER!"
Sans grinned and shrugged his shoulders and Mettaton laughed, "Ah brotherly love, gotta love it, great for ratings, well Underground, lets give this skeleton, a Skele-Ton of applause!"
"NOT YOU TOO!" Papyrus cried out before everyone began to cheer and clap for the underdog victory.
Undyne rolled her eyes but shook his hand, showing at least enough respect for him before they walked off, so Mettaton could continue his show.
Yep life in the Underground, never a boring thing that's for sure.