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[Undertale AUs] Yandere! CORE!Frisk x Human! Male! Reader

Requested by: Andrewseestou

Things change really fast. One second you're minding your own business then next some weird child can be asking—more so demanding—you to go with them to some place you've never heard of and never come back to your home.

"Uh, excuse me." (Y/N) says angrily, "Get out of my house!"

The child tilts their head, "I can't exactly do that. I am not spatially bound to one location like you are."

"Get out of my house!" He repeats.

"Ah, it seems my explanation hasn't made sense to you." The child is suddenly directly behind them, "I can't really leave your house, I will still be here. You just won't see me."

"What do you want?"

"I want to warn you." They don't move.

He stares at them, silently telling them to continue.

"You're in serious danger if you stay here."

"Ok, first let me ask. What are you?"

"I am Frisk, I am a human who has been scattered across all of time and space. I said earlier that even if I were to make myself unseen, I would still be here. That is because I am omnipresent, I am everywhere at once, but I only have one body at a time." They've obviously dealt with this sort of reaction before, they'd likely been expecting it, "Is there anything else you'd like me to explain before I tell you why you're in danger?"

"Uh huh, so, you see everything?" (Y/N) summarizes.

"Yes."

"All the time?"

"Yes."

"How old are you?"

"My age has been irrelevant since I became scattered across time."

"Uh huh, so judging by the stripes, you're a kid..." He says thoughtfully, "I'm not sure whether I'm self conscious or disgusted." He shudders.

"Can I please explain why I am here?" They frown.

"Uh, ok...?" He shrugs.

"(Y/N), you're in danger." Frisk begins. "In every timeline I've found you in, you always die and it always starts the mob fights between humans and monsters."

"Uh huh..." (Y/N) tries to suppress a shudder as an unsettling feeling settles in their gut. How many times has this kid tried to prevent his death? Why do they know his name? That seems like something that is throw-away knowledge from a historical standpoint... It doesn't help that their expression is very hard to read. "So how does that happen?"

"You're killed accidentally by an attack that escaped a pair of sparring monsters. Humans use this as proof that monsters are dangerous and need to be destroyed."

"Ok, so are you trying to prevent that or stop me from being the victim that causes this." He rolls his eyes and crosses his arms, "That seems like an inevitable problem."

Frisk's hollow eyes narrow in what (Y/N) thinks is annoyance.

"Are you saying you'd like to die?" They ask, mimicking his posture.

"No."

"Then come with me." They offer him their hand.

"And if I don't?"

Silence. Neither of them move.(Y/N) even feels awkward breathing as they stare at him, their hand still outstretched.

He cautiously takes their hand.

"Good choice." They lead him over to the door. "Now open this door while thinking about going to a place called the Omega Timeline. That's a place I've made for the inhabitants of the multiverse to live peacefully and in safety."

Ok, (Y/N)'a gut tells him this is a trap. This sounds so sketchy.

"Will I be able to come back?" He asks.

"I don't see why you would want to." Frisk says, "You're still in danger while you're here."

"That didn't answer the question."

"Yes, you can get back here from there, but you can't go to other universes." They answer.

He pulls open the door. Beyond it was a place that looked like a white void stitching many places together. It's... actually kind of cool.

"I can show you around if you'd like." Frisk is suddenly on the other side of the door, "There are quite a few empty houses for new people who want to live here."

"Uh... sure?" He steps inside, closing the door behind him.

"Follow me." Frisk leads the way.

"Where is everyone else?" (Y/N) asks, looking around at the deserted area.

"We're on the outskirts of town. Everyone else is closer to the square." They explain.

"Ok...?" His uneasy feeling returns.

"Here we are." Frisk stops in front of a quaint house. "This is one you can have."

"It's... nice?" He approaches the front door as they step aside, from behind it felt like their gaze bore into him.
He opens the front door, hoping the inside will be enough to shake the feeling. It's an ordinary house. There doesn't seem to be anything off about it.

"Uh, Frisk?" He looks around after his brief exploration.

"Yes (Y/N)?" The omnipresent child appears in front of him.

"Gah!" He jumps back, not expecting their sudden appearance.

"Oh, I'm sorry." They grimace, "I forgot that people who aren't used to me doing that often freak out when I do."

"Yeah, I wasn't expecting that..." He awkwardly scratches the back of his head.

"Did you need something?" They change the subject.

"Uh, not really, I just wanted to check if you were still physically here."

They nod, "I am going to be "physically" leaving, if you need help, you can certainly go into town and they will help you get adjusted."

"Uh, ok? Bye?" He waves.

"Bye." Frisk waves goodbye, then heads back to the antivoid. "I suspect you have done as I asked you?"

"Yeah, yeah, whatever." Error Sans waves his hand in dismissal, "I still don't understand why you wanted that place destroyed, it was pretty boring."

"Thank you, Error. Though I won't be letting you into the Omega Timeline, you do have my thanks." Frisk grins.

"Whatever." Error rolls his eyes, "I'm gonna go find another glitch to deal with." With that he leaves.

But Frisk was left with a sense of triumph they hadn't felt in quite some time. They had finally tricked one of the versions of (Y/N) and gotten them stuck in the Omega Timeline without them suspecting a thing—actually, that's probably false, they likely suspected something... but it's too late for that now. They were trapped where they would be safe, where Frisk could keep them safe, forever.