My only one(undertale au x fem reader) oneshot

ying and yang: Nightmare x reader

(couldn't help it.)

(Y/n) POV

I sat beside Nightmare as he silently read his favorite book, Not a bad guy. It's about a boy who turned evil cause of all the people who hated him, but one day he met this girl who doesn't want to hate him for what he does. It was quite interesting. I read it two times already.

Nightmare's POV

I felt so loved when (y/n) was around. My brother would always be busy with the town's people. They needed Dream, they hate me... But (y/n) was different. She said something about ying and yang once. She told me that light couldn't survive without dark and dark couldn't survive without light. They need each other for balance to keep the world at peace. That's why I love her so much.

Two days later, I found out that (y/n) was getting beaten up by the town's people. "Why are you helping someone so evil?!" "Do you wanna turn bad like him?!" "You might as well just die!" They yelled. "He's not a bad person. You guys are just judging him. Nightmare's a nice intelligent person. You guys are just bullies!" (Y/n) shouted before she was kicked by a boy. "Shut up, you don't know what you're talking about!" The boy yelled. "(Y/n)!" I yelled running out of the bushes. "There he is. Get em!" A girl yelled "NO! DON'T!" (Y/n) pleaded as they rush towards me. I couldn't fight against these people, so I ran.

(Y/n)'s POV

No! I can't let them hurt Nightmare. He's already in enough pain as it is. I stumbled up and tried walking towards the direction the angry mob went. I just hope I'm not too late!

Along the way, I spotted Dream looking around with a worried look. "Dream." I said almost barely above a whispered. "(Y/n) are you okay?! What's with all this negativity?!" He asked holding me. "It's some of the town's people. They want to kill Nightmare." I said before calapsing on my knees. "Stay here and rest a bit. I'll stop them from trying to harm my brother." Dream explained placing on the soft ground before leaving. As the world faded, I heard people screaming.

Nightmare's POV

I killed almost every person who dared hurting (Y/n) and I. "Brother?" I heard and oh so familiar voice. I turned around to see my brother. "What did you do?" He asked. "I'm killing every being here that dared to hurt (y/n) and I. They all have to pay someday and that's today." I replied before striking at my brother, but he dodged. "I don't want to hurt you! Please don't do this!" Dream pleaded "You know what, I'll leave, but I'm taking someone with me." I said before teleporting to were I felt (y/n)'s precense. She was lying on the ground bruise and bloody. I picked her up with my tentacles. "BROTHER DON'T LEAVE! WE CAN FIX THIS!" Dream shouted. "I'm going somewhere we're you can never find us. I'll spread negativity to all these useless au's. One by one." I said before opening a portal and jumping through making sure I close it soon after.

(Y/n)'s POV

Two freaking years! It's been two years since Nightmare became evil and won't let me leave this castle. All the other bad sanses get to leave and do their missions.

I was in the throne room now trying to reason with Nighty. "I promise I'll just be in the gardens." I said "No and that's final." Nightmare said before using his tentacles to escort me out of the throne room. I heavily sighed going to my room. At least I convinced him not to keep any hostages or prisoners. "Ppst." What the heck was that? I looked around to see Dream and Ink. I panicked. "You guys shouldn't be here." I said walking over to them. "We're here to save you. Come on before-" "Before what? I come and kill you." I heard Nightmare say. I was then grabbed by the waist and hoisted over their shoulders before bolting. "GET BACK HERE!" Nightmare yelled as Ink made a portal and jumped through it.

Nightmare's POV

They did not just my girl! I punched a near by wall, making a big dent. That b***! (Nightmare the swear jar!) They stole what rightfully belongs to me! I then made a portal to where they possibly can be.

(Y/n)'s POV

"Guys he's gonna go rage mode when he finds us." I mumbled sitting on the couch. Nightmare can be a big mad five year old when it comes to finding me.

Flashback to a month ago

Nighty and I had got into an argument about whatever the heck he started yelling about till the guy whacked me on the head and called me and idiot. "Jerk!" I shouted before running away. I hid in a cabinet in the kitchen for like thirty minutes cause I knew he go looking for me.

Suddenly I heard him yelling and crashing noises. "BOSS CALM THE F*** DOWN!" I heard swapfell yelling "SHUT YOUR DIRTY MOUTH!" I heard Nightmare yell before another crash rang through out the castle. I crawled out of the cabinet seeing that everything was almost upside! "What the heck Nightmare." I mumbled. He must of heard me cause I heard him stomping down the hall till the door bursted open. He had swapfell in one of his tentacles. Nightmare dropped the poor guy as he stomped over to me. "Where the heck were you?!" Nightmare shouted. "I was hiding in a cabinet while you were having a temper like a five year!" I shouted. He then picked me up and teleported to his room. Nightmare then cuddled me. Mood swings much?

Flack back end

My thoughts were then cut off when to freaking door slammed open and fell on the ground. "Hey Nighty." I said. "Nightmare, why did you distroy my door?!" Dream yelled. "You need to stop stealing from me!" Nightmare growled before picking me up and just teleporting to the castle. I hugged him as he sat down hugging my waist. "I love you..."  Nightmare grumbled. "Me too you big baby." I said giving him a closed eyes smile. Even with Dream here, Nightmare will always be my ying yang soulmate.