A/N Hey Guys and Girls I've decided to write another fanfic involving Princess Luna vs Nightmare Moon because I decided that there should be something about both these characters who share the same body and there should be something about Luna battling her dark side before it tries to break the surface and take over her again. Please Read and Review Enjoy.
It has been many years after Princess Luna had returned to herself after being imprisoned as Nightmare Moon on the moon and all was peaceful with the Princess of the Night, however, she felt a growing presence in her for the past few months because it was soon approaching Celestia's birthday. The preparations were being made to celebrate Celestia's birthday in two months time by none other than a certain pink earth pony, Pinkie Pie. Celestia was out attending to her Royal Duties during the day, Luna was roaming the castle's halls since she could not sleep for some reason today, she entered the ball room to find many streamers and a massive banner saying, "Happy Birthday Celestia" on it, Luna could only giggle to herself when she saw Pinkie Pie already blowing up party balloons two months prior to Celestia's birthday, she approached the pink pony and said behind her, "Don't you think it's a little early for that," Pinkie whipped around and a balloon bursed because she had over-inflated it. Pinkie bowed her head in being in the presence of her princess, "Sorry your majesty I... I... was just..." she was lost for words, Luna lifted her head and smiled gently at her, "There is nothing to be sorry for I was just admiring your work so far any way," Pinkie immediately smiled like her Pinkie self again, "Thanks your majesty I like to know that an important pony like yourself admires my work," Luna laughed kindly, "Oh Pinkie I told you just call me Luna," Pinkie relaxed a bit after that, "Okie dokie Loki," Luna giggled at the rhyme Pinkie normally used and turned to leave, "By the way Pinkie love the streamers, hopefully you can do my party," she said before closing the door.
Luna continued to wander the halls of the castle again and went into the kitchen to see the design for Celestia's cake, as she entered she saw the Royal Baker with Mrs. Cupcake looking over the design for the cake, they acknowledge their princess entering the kitchen and they greeted her in respect, Luna walked over to the cake design and saw a cake in the shape of Celestia's head resting on her cutie mark sun, she smiled at how amazing it looked, "I love the look of it, it's truly beautiful and I have a good feeling that she'll love it too," she said to the two chefs standing at her sides, they bowed their heads and thanked her. Luna noticed the clock and saw it was nearly time for Celestia to return, she greeted the bakers again and left to the courtyard where the Royal Carriage rested after its long journey and out stepped a tall white alicorn with a flowing mane of blues, green and pink the same with her tail, Luna had greeted her like she always did, "Greetings sister, how was your travels?" Celestia just gave her a hug, "Luna you know you don't have greet me so formally we are sisters not different rulers," Luna hugged her back and walked with her to her chambers. When they entered the bedroom Celestia went out to the balcony still with Luna at her side she lowered the sun and Luna raised the moon, Celestia told Luna of her travels today and explained that it was mainly land disputes. They sat down to dinner and they conversed about their days, but, Luna did not mention the party or the cake design for she wanted that to be secret until the day of Celestia's birthday. Luna had wished Celestia good night and attended her duties of the night, but, when she entered throne room she heard laughing, she looked all over to see nothing, then again the laughter, she called out, "Who's there?" the laughing continued and Luna followed it until she reached her bedroom and continued to follow the laughing.
She saw a shadow and followed it to her mirror on the wall she looked into it and saw herself staring back, she shook her head, "Okay Luna you're just hearing things, probably because of the lack of sleep," she was still looking into her mirror, and as she turned to continue her duties she heard a familiar cackling coming from the she turned back towards it and saw her, Nightmare Moon, she was smirking evilly back at her, "What do you want?" she asked the reflection, "Well my dear did you really think you could ever get rid of me?" she answered back. "You're nothing just a reflection in a mirror and when I close my eyes you're gone," Luna turned her back on the mirror now, the evil laughing continued, "Don't you know you foal I am you," Luna's eyes began to tear up she turned back to face a smirking Nightmare Moon, "You are not me, I'm a good mare and thou canst not change me at all," "You know your true colours, whenever you look into a mirror I'm there, whenever you are alone I'm there and when Celestia banished you I was the only one who was there for you," Nightmare moon began to laugh again. Luna felt something in her at that maoment and she felt a feeling in her she had not felt in a long time, Nightmare Moon continued to laugh at her, "Who was it that banished you to the moon? And who was it that decided to take our duties over the moon and who stooped us from making a beautiful eternal night?" Luna stared back into the mirror, "They did that to save me from you," she said growing more impatient, "They are the ones who shunned you from pony kind," Luna bowed her head tears streaming from her eyes, "Go away Nightmare Moon," but Nightmare was not finished yet, "You have no friends and the ponies shun you and your own sister locked you away fro..." before the reflection could finish Luna had smashed her head into the mirror, shattering it and cutting her face between her eyes, tears still streaming down her face.
At that moment Celestia entered the room and found Luna curled up on the floor crying she ran over to her sister and saw the broken mirror and the bloodstains, she shook Luna and picked her up in her hooves, "Luna! What did you do to yourself?!" a tone of distress in her usually calm voice, Luna did not answer, immediately Celestia called the nurses from the Canterlot Castle hospital wing and told them to take care of her they did she asked and rushed her off to the hospital wing. Celestia raised the sun and lowered the moon since Luna was in no state to do so, she used her magic to clean the bloodstains and looked at the broken mirror and left it as she was interrupted by the Royal Guards who needed help with issues that needed to be disputed. Few hours later passed and Luna had awakened to see herself laying in a bed that was not her own, she looked around and saw that she was in the hospital wing of Canterlot Castle, she gasped when she felt the stitches that were now where her cut was, she then sighed at realising what had happened the night before, she later heard the doors open and she saw her sister with a concerned look on her face, Luna turned away in her bed, "Luna what did you do last night?" Celstia clearly concerned for her, Luna turned to her again, "I was doing my rounds around the castle as usual and then I heard laughing," Celestia raised an eyebrow at hearing this and bid Luna to continue, "I followed the laughing into my bedroom and then saw a reflection in the mirror..." Luna was reluctant to say these next words, "I saw... Nightmare Moon," she began to cry heavily at hearing the words she had just said, Celestia hugged Luna and said nothing as she processed what was just said to her. A week after the incident Luna had returned to her normal duties during the night, but, she had company continuously trying to persuade her into what she didn't want any part of for she never liked that part of her at all.
It had been month since Luna had smashed her mirror with her head, her stitches had been removed and her scar was barely visible though, she was in her room trying to relax after Celestia said she would take the night, after all Twilight was spending the night studying
with her again, Luna was in her room having nothing to do except stand out on her balcony and look at her sister's produced night and saw that it was not as beautiful as the ones she does, she began to hear a voice in the back of her mind, "You see how she took over our duty again and she didn't even do it properly," Luna turned to the moon and said, "Yes she has no idea on how to make our beautiful nights like we can," Luna hadn't realised that she was using the royal "we" like she normally did when she adressed her subjects whenever she spoke to them, she saw her shattered mirror and repaired it so she could see herself, again she saw Nightmare Moon staring back at her, but, Luna didn't flinch at her this time and continued speaking as if speaking to Nightmare Moon if she was actually there, "My sister has no idea on how to make a beautiful night like ours," Nightmare only smirked at her, "Yes give in to your jealousy and take your rightful place as the only ruler of Equestria and there can only be one Princess," Luna suddenly snapped out of her conversation and turned away from it. As she turned towards her bed she saw a painting Celestia raising the sun and she saw all the ponies of Ponyville rejoicing and frolicking in her sister's sunshine and she tore the painting in half with her magic, she turned again to see her and Celestia at their coronation and tor it in half too so just she could be seen in the painting. Luna went ballistic in her room tearing and breaking anything that reminded her of Celestia and how she was worshipped for rising the sun she even changed the night to one of her beautiful ones, she turned back to her mirror and with an insane cackle she ran straight into it face first cutting it more severely than last ime and the wounds were worse than previously.
Celestia had heard the commotion and saw Luna tearing her room apart with her magic and her body tears and blood streaming from her face not caring what physical injury she caused herself, she was laughing insanely now growing worse and Celestia restrained her in a magic proof shield, Luna screamed at her sister realising what had just happened, Celestia called the royal unicorn guards to restrain her until she was placed into the Canterlot Castle's hospital wing again, but, in the mental institute. Celestia saw her sister being restrained into a bed with restraints holding her hooves and her horn while they injected her with a sedative to calm her down and she slept soundly through the day as Celestia rose the sun again, once Celestia had heard that Luna had been deemed safe to see her with supervision Celestia went with Twilight to the hospital wing to see her sister. Celestia and Twilight sat across Luna who had been released from her straight jacket so she could speak to them, Twilight took notice of Luna's stitches on her face and the bruises she had from going insane the other night, Celestai then spoke, "Luna why in Equestria would you do this to yourself?" Luna only began to chuckle, Celestia looked concerned towards her, "What is so funny Luna?" she asked with concern and a bit of an annoyed tone in her voice, Luna looked up to her sister and Twilight and said, "It's not Luna..." and after a long pause between the sentences she looked into her sister's eyes, "It's Nightmare Moon," Celestia and Twilight gasped as Luna began to cackle like Nightmare Moon normally does and within seconds the unicorn nurses restrained her again in her straight jacket and clamped her horn and tried to drag her away, but, she was too strong for them, they had to get more nurses to restrain her then and their and before she was taken away she called to her sister, "You foal I'll be back for I am Nightmare Moon," those last words she spoke in the Royal voice.