Undertale/Au's x reader.

Yan! x reader x Blueberry

*I see yan as blueberry's second personality that does all the yandere stuff. Sorry if this one is confusing. You can tell if yan has taken over because blue will have red eyes.*

All I ever saw was darkness..

My life was hidden away, no one could see me, only Blue knew I was here.

Sadly I was all of his negative emotions that he kept locked away in the back of his mind.

One day I was just lazing around in Blues head until our eyes  met with a beautiful (e/c) pair.

I knew Blue loved her at first sight, I could feel it too.

Love was the only good emotion I felt when I saw her.

I was addicted to this new emotion.. For years all I ever felt was negativity.

I was jealous over Blue, he kept a sweet face with this happy go lucky personality.

It made me sick.

-----

I learned her name was y/n such a beautiful name, it has become my favorite name.

Blue and the human have become very close, they were inseparable, they went everywhere together.

I still wonder if she could see me in his eyes, if she could.. She never asked blue about it, the red spark in his eyes, it was me.. Sure it might be faded.. But I'm still here.

-----

Blue was sitting on the couch when suddenly y/n ran into the house and hugged us.

She had been crying...

Our eyes widened.

"Y/n what happened?" Blue asked her.

Her tear stained face looked down..

"Bf/n.. He.. I found him cheating on me.."

Blue looked at her sadly and hugged her.

I looked away from the sight..

How could someone break my y/n's heart? He will pay.

-----

Later that night, my void space went darker.

Blue had fallen asleep, he ran past me to his dream land..

I shook my head and once I made sure he was gone, I took control.

I looked down at my hands clenching and unclenching them.

It felt so nice to have a body, I smile.

Turning my head I see a mirror, I looked exactly like blue just my eyes glowed a soft red, and I had fangs for some reason.

I teleported down stairs.

There she was, I finally could see her in person.

My hand brushes through her hair, I bend down and kiss her forehead.

I make my way to the kitchen.

Opening one of the drawers I see a large kitchen knife.

My smile widens, I take it and hide it in my boot.

Now.. Where is that a** who broke y/n'd heart?

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(Gore and blood warning)

I found out where he lived thanks to my loves phone.

I teleported inside, his house was messy and gross, and don't even get me started on the smell..

I spot him passed out on the couch.. Shirtless..