Sans x Magic! Reader x Chara: Under the Surface

[0.4] Something New

「Killer Y/n POV」

The east wing of the castle was colder and darker than the west wing like a complex with winding corridors that only lead to more passageways and it was as if the rooms were changing on their own.

"Hey, you're the new recruit." You casually stopped as you passed by him in the corridor.

"I forgot Killer Y/n patrols this area." Chara groaned. "Great... Just great."

"Yeah, what's it to you?" Cross scoffed at you, disinterested in engaging with you after the things he had heard from Killer Sans.

"Friendly, aren't you?" You circled him, your voice heavy with sarcasm.

"Give me a break, sweetheart." Cross turned to leave as he referred to you with the same level of sarcasm.

"Listen to me, tough guy. You just arrived at the toughest place in the multiverse and I'm offering to be your friend." You didn't hesitate to turn to aggression faster than the blink of an eye. "Trust me. In a place like this, you're gonna need friends. So it's up to you. You gonna play nice, or what?"

"Work with me here!" Chara complained as only Cross could hear his voice. "Don't get on this Y/n's bad side or we're both going to suffer the consequences of your actions."

"Yeah, okay." Cross shrugged indifferently, and you smiled.

"Good. So how about I show you around the east wing?" You rested a hand on his shoulder and started to lead him out of the endless corridor. "By the way, Nightmare Y/n messes with the environment sometimes... but it was fun watching you walk in circles like a lost puppy."

Nightmare's castle had four wings being north, south, east, and west while the core of the castle was the source of negativity.

"Feeding time at the zoo..." You spoke as you both overlooked the break room where all of the recruits gathered for lunch like a cafeteria. "Okay, here's the deal."

You motioned to another Sans with a gaping hole in his skull and a blood red eyeball in his left socket that was hungrily eating a chicken leg.

"Over there we got Horror Sans." You nonchalantly pointed out. "Of course he's a complete social outcast."

"He looks harmless." Cross commented as you both watched him devour his food in peace, not bothering anyone.

"He's actually a sneaky bastard." You narrowed your eyes in annoyance. "His turf is the south wing."

At the next table was another Sans with his worn out blue hood pulled over his head sleeping soundly.

"And that's Dust Sans. He thinks he's tough, but he's really just Classic Sans with his hood on." You told him with a suspecting tone in your voice. "He hangs around the north wing."

"Yeah, and has dust all over his shorts." Cross added.

"Very observant, Crossy boy." You proudly smiled. "Now over there is Killer Sans. He sucks up to Nightmare for obvious reasons."

Cross watched the killer skeleton he had quarrelled with on his first day sharpening a knife that glistened in the darkness of the castle.

"Wouldn't advise messing with him... at least not yet." You coolly crossed your arms, remembering there was another version of yourself wandering around somewhere. "And last but not least... Nightmare Y/n. Definitely avoid them."

"I'm not scared of them." Cross defiantly said, to which you only responded. "You'll learn."

「Classic Y/n POV」

Sans slowly blinked open his sockets to see your blurry image looming over him with worry evident in your charming red eyes.

"Sans..." You whispered, wrapping your arms around him in a hug. "I... I was so worried about you when I heard you collapsed while playing volleyball with the others."

"Heh... I'm okay, kiddo." Sans patted your head then glanced up at the clock to see it was noon and sighed in relief he wasn't unconscious long.

"Sans?" You asked, looking up at him as he hummed attentively. "Can I see your soul?"

"That's uh..." Sans awkwardly chuckled when he realised you were serious. "Kinda sudden, isn't it?"

"But you check my soul all the time..." You told him as you leaned in to get a better look at him.

"I dunno..." He started to sweat from his skull as he averted his pinpricks from your intense gaze.

His soul was then forced out by your magic, and you clasped your hands over your mouth as you stared at the soul in front of you that consisted of just a half with a red X constricting it.

"Who did this to you?" You asked in a quiet voice that broke his heart.

"Sweetie..." He softly said and cupped your face with his skeletal hands so you would look up at his gentle pinpricks. "I don't want you going around looking for whoever did it, alright? It's dangerous and... I'm fine."

「Cross Sans POV」

Cross checked his soul again, feeling the need to make sure it was still intact as the upside down heart floated freely in front of him made up of the stolen half of another Sans and Chara's remaining determination making up the second half.

"Stop showing off your new soul." Chara rolled his eyes in annoyance, then saw you. "It's Killer Y/n. Let's go say hi. If we get them on our side, our lives here are going to be a lot easier."

"You know what, Horror? You're right. Cross is pretty dumb." You purposely said loud enough for him to overhear as he entered the room.

"What'd you say about me?" Cross aggressively asked, offended.

"I just said that you must be pretty dumb to let your brother die..." Horror shrugged, shuffling back a bit as the other skeleton stepped closer.

"Relax, Cross. All he said was that you must be dumb." You patted his back as if you were old friends and slyly added. "Or maybe you're all messed up because you came from a broken world."

"What did you say about me, you bastard?!" Cross grabbed him by the collar of his bloodstained shirt.

You smiled to yourself in satisfaction as you left the two skeletons to fight each other, hearing the clash of a knife against an axe and gaster blasters going off.

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Killer Y/n nicknames him "Crossy boy" and Lust Y/n calls him "Kris" or any other mispronounced variant of his name to tease him.

Nightmare Y/n has an ability of illusions which was how they could control the atmosphere described in the first paragraph. They use this ability in combat too which makes them very tricky to fight.

I don't really want to retell everything that happened in Underverse in written form, but basically Cross stole half of Sans's soul then Sans got hurt playing volleyball with Frisk and the other monsters because he is weak now.