Yandere Undertale Au's x reader oneshots

yandere blueberry!sans x shy!reader

Y/n p.o.v
            You and sans, basically you call him blue and sometimes blueberry cause he's so cute and you can't resists the cuteness neither avoid it. You we're on asgore's ruins alone with paps and sans was just outside "so want to go at muffets?" Paps ask, you nodded slowly as paps reach out for a hand, you blush since you'd have a crush on papyrus and never told anyone "sur-sure" you accepted paps and go with him at the muffets, while you we're holding paps hands you felt something watching you

Blue p.o.v
             'How dare...he touch my y/n...he'll pay even though he's my bro...but I won't let him win his heart..y/n is mine..only mine....alone' I got up and go to the back of muffets restaurant. I knock the door as I go up in the door so if she open it she'll not gonna saw me. Muffet then open the door "is somebody t-" I then cut off muffets mouth and fall in her (a/n: not fall in love!!!!) And pull the knife out "b-blue what are y-" before muffet can finish his words, I sliced his throat deeper as I close the door using my foot so she can't escape, and then sliced his hands and foots and then her precious stupid face as I watch him slowly turn to dust. I then throw the things that left when muffet turn into dusts and take the dust off my clothes and got inside in muffet to see paps with y/n seating on the counter talking

Paps p.o.v
             I let out a sign while me and my y/n talking '*sign* I love talking to him' I thought as blue approached to us and pull my hoodie "paps can you come with me for a minute" "sure bro" me and blue left y/n. "so what is it bro" "paps...do you love y/n?" Sans ask, I blush and look away "n-no b-" "*giggle* y/n is mine and I'll win his precious heart not you!" Blue said and pin me on the ground, I couldn't help it but throw some bones at blue and my left eye-pupil glowed orange as then a knife was throwed on my left eye making my glowing orange eye-pupil disappear. I then pull the knife out off my eye-socket  and groan in pain "why share you d-doing this sans?" I said and blue just giggled and grab my chin and a sharp object hit on my throat that I just realize blue is slicing it

Blue p.o.v
              After of stabbing and killing all the monster who ever talked to my precious y/n. I go to the muffets restaurant to see she was waiting, I then sign and pretend to be innocent "hey y/n paps said he'll not be here for about an months so we should probably go home" "w-where d-d-did p-paps go?" Y/n said said with his cutest voice ever making me turned on "I dunno but he told me to protect you so let's go home" I smile "o-o-okay" y/n said as I grabbed his soft skin and teleport me and her in the house carrying him in bridal style, she then blushes cute "b-b-blue you d-don't h-h-have to d-do this" she said and mumbled while blushing. I then place her on the couch and wait him to go sleep.then she closes his eyes so cuteful, I then kisses his cheeks and whispered "your mine now...mine only...mine alone....I love you......