Yandere!Under verse x Reader

Bravery and Nightmares

A/n: sorry for the wait, but here's the next chapter. I'll start tallying the apple brothers and Y/n's age now. Y/n: 8, Nightmare: 13. Dream: 13 in total, 9 physically. The updated yan list is at the bottom of the chapter, and I am sorry if this isn't my best work. Going through some emotions right now and school

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It's been a few years since Y/n was brought to Memorytale and had their memories of Dreamtale, the apple brothers, and Nightmare's castle. Y/n has gotten adopted by Memory and made friends with the human souls, even though Ruyi(Asriel) and Kyodai(Chara) haven't come back yet, and Boken(Frisk) has yet to fall. Saturn(Justice), Alex(Integrity), Venus(Kindness), and Agnus(Perseverance) have already fallen, so Y/n is friends with Catherine(Bravery), who they like because big sibling vibes....and that's where we are currently.

Catherine:...and that's why I'm here, to look for my brother and sister

Y/n: :0...uh, I think I saw the integrity soul and the kindness soul....I just gotta ask Chisiki(Alphys) if she knows where they went : D

Catherine, nodding: thanks kiddo

Y/n nods and leads Catherine to Chisiki, unaware that someone is watching them. The duo keep walking and Catherine wipes her brow, the heat getting to them. Catherine glances down at Y/n.

Catherine: how are you not hot? You got more layers than me on!

Y/n: huh? Oh! Dad taught me this!

Y/n extends their paw and a layer of ice covers it, before slowly melting due to the heat. Catherine blinks.

Catherine: huh...smart.

Y/n, nodding: uh huh! C'mon!

Y/n's wings flutter and they keep leading the bravery soul to the scientist. Catherine spots something and squints.

Catherine: is...is that a dragon-

Y/n: huh? Oh, that's just Mrs.Beris. Her name is Rui and she's nice...wanna go talk to her?

Catherine:...no thanks. How much longer until we get to the lizard?

Y/n, blinking: huh? Oh, not long! I think that's her right now! Ms.Chishiki!

Chishiki blinks and looks over, eyes growing wary once she sees Catherine, an almost wistful look as Catherine seems to return the sentiment. Y/n squeaks and flies over, with Catherine following from the ground. Chishiki looks up at Y/n.

Chishiki: h-hello Y/n. W-who's your f-friend?

Y/n: this is Catherine! They're looking for Alex, the integrity soul!....oh, and Venus the kindness soul!

Chishiki: I-I see...I-I can take care of t-this. T-thank you, Y/n

Y/n, nodding: mhm!

~~timeskip~~

A/n: Y/n: 18, Nightmare: 23, Dream: 23, 9 physically

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It's been 10 years and all 6 human souls have fallen. Y/n is very upset at this, but doesn't let it bug her because Memory and Pazuru have been training her in memory magic so they are prepared to go out into the multiverse when they are older.....they can only keep Error and Ink out for so long, as well as distract them or just straight up mess with their memories...like they need help with that in the first place...anyways-

Y/n is allowed to go to certain au's that Memory have pre-approved of, like Memorytale itself, Reapertale, Aftertale, Outertale, Underswap, and Storyshift. Y/n agreed to this, but Memory made them swear to come back if the genocide route starts. Y/n does not like this since they believe she can help, but reluctantly agrees. ...but Y/n, being the free-spirit they are, goes against Memory's back and gets out their double edged scythe, making a portal and goes through it.

Y/n looks around, feeling the negativity from this place and spotting a castle in the distance. Y/n opens their wings and goes to fly, but something wraps around their ankle and yanks them down, causing them to fall down with an 'oof'. Y/n then feels overwhelming negativity, so their own aura combats it now that they are old enough and know how to do that. The thing unwraps from their ankle, allowing Y/n to stand up, which they do. Y/n stands up and brushes their pants off with their paws and turns around.

Y/n: well, that was rude. Who are you?

Y/n looks at the strangely familiar goopy octopus and tilts their head, their wings twitching as they see the shock in it's singular cyan eye.

Y/n: do I know you? You look familiar somehow....

Nightmare: I-I...how? How are you alive?

Y/n: Do I know you??

Nightmare looks at Y/n, studying them and wondering why she doesn't remember. Sure it's been awhile, but surely she couldn't have forgotten him so easily...right?

Nightmare: It's me, Nightmare.....your brother

Y/n, confused: brother? I wasn't aware I had siblings....You look familiar somehow, so I'm sorry I forgot you. If you truly are my brother, then why don't we try to get to know each other again since I am sure it has been awhile since we have last seen each other

Nightmare, nodding: I'd....I'd like that, sister...follow me inside my castle

Y/n, impressed: your castle? It's huge!

Nightmare, nodding: it is...and I am the ruler of it...the king and guardian of negativity!

Y/n, whistling: wow, that's some pretty cool titles octopus man...so you're a guardian to? That's cool. I'm the guardian of memories...and my names Y/n. what's yours, octopus man?

Nightmare, sighing in annoyance: my name isn't "octopus man", sister...it's Nightmare

Y/n, blinking: huh...so if you're Nightmare, the guardian of negativity....then doesn't that mean that there would be a Dream who is the guardian of positivity?

At this, Nightmare gets noticeably agitated and doesn't answer, leading Y/n inside....and from there, the two lost siblings start to get to know each other better, telling each other stories...if only Y/n had listened to Memory's warnings...

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Yan List:

Passive: platonic older brother

Nightmare: platonic older brother

Dream: platonic younger brother(only reason he is younger brother and not older brother is because of the stone prison)

Reaper: platonic dad

Life: platonic mom

Geno: platonic friend(he fren shaped)

Blue: platonic friend(yanberry anyone?)

Classis: platonic friend(the most normal one)

Fresh: platonic friend

Dust: platonic friend

Horror: platonic friend

Outer: platonic friend

Memory: platonic dad

Soul: platonic dad

Ink: romantic yan(and he's soulless!....good luck)

Error: romantic yan

Cross: romantic yan

Killer: romantic yan

???: romantic yan

I am hesitant on whether there should be more romantic yans or not. Is there anyone you would like to see as a yan? It can be a frisk or a chara, but it has to be in reason.

Word count: 1118