A Nightmare On Nightmare Night
Prologue: Angel of Death
A Thousand Years Earlier
An alicorn mare ran through the streets of Canterlot. It's coat was a deathly white, it's mane and tail pitch black with spots of red blood covering them. It has no eyes. Instead icy blue orbs of light inside the eye sockets. It's wings are nothing more than bones. Revealing a patch of fur that has been ripped out where the wings are connected to the body. The mare runs through the streets as an angry mob of unicorns, pegasi and earth ponies chased after her. Most notable of the unicorns is an old bearded unicorn wearing purple robes covered in stars, with matching hat.
The mare finally runs into an abandoned house in the projects of Canterlot. Where mostly the earth ponies lived. The angry mob stopped at the door. The robed unicorn held up his hoof to stop the mob from entering.
“Why stop us Starswirl?” his student Clover the Clever asked.
“I'll handle the Spirit of Death myself Clover.” Starswirl merely said before entering the house. The mare watched him enter the dark house. Starswirl saw the mare's horrifying blue glowing eyes, as he entered.
“Decided to finish me off yourself Starswirl the Bearded?”
“No Azrael. No mortal can destroy the Spirit of Death when it has taken a host and gained enough souls to reach it's maximum power,” Starswirl replied. “But you have to face your punishment for what you have done to the seventy-five ponies you've murdered. Including your host.”
“What do you propose?” Azrael asked.
“I propose that you serve a thousand years merely leading the souls of dead ponies to the afterlife for judgment.”
“Once a thousand years are over?”
“You are free, but whoever is leading Equestria at the time will decide what to do with you,” Starswirl said. “You may have to lead the souls of the dead for eternity. You may even have some time to find a new host and continue your old ways until you're caught again.”
“You have a deal.” Azrael replied with a smile.
“Good.” Starswirl ignites his horn and cast a spell on Azrael to send it back to the afterlife.
Present Day
Celestia lowers the sun for the day so her sister Luna can raise the moon. Luna does so and decides that the rest of the night she can watch her little ponies in their dreams.
Walking through Canterlot on a foggy night, Princess Luna looks all around her to see if she is being followed. She should be in a pony's dream right now. But this isn't a dream for a pony. Luna is starting to think this her own dream but why is she dreaming when there are ponies who need to have their nightmares turned to pleasant dreams.
Luna continues walking through the streets looking in all directions to find any pony present. But there are none to be found. The streets were getting darker and the fog got denser. Luna started to get scared. The Princess of the Night is starting to get scared. She had to stay strong, she had to overcome any fear she felt. Yet in this misty pitch black version of Canterlot. That was pretty much impossible here. She walked down an alley and ignites her horn for light. As it is now pitch black out. No moon in the sky and no stars were visible. It was eerie in that alley. Anything could attack her in her domain, and Luna knew it. When she reached the end of the alley, an evil demonic giggle could be heard behind her.
“Who's there!? Who darest attack us in our domain!?” Luna said. Using the old Canterlot language and voice. As well as referring to Nightmare Moon who still lies dormant in her body. A skeletal pony walked into Luna's light. Laughing softly and menacingly, as it walks closer. It's glowing blue eyes inside the empty eye sockets send a chill down Luna's spine. The hair on her mane and tail stand on end. As this definition of death itself nears Luna, she simply charges up a spell and fires at the pony. The spell flies at the pony then unexpectedly flies towards the sky.
“Who are you?” Luna asked.
“Pity... It seems that I have been forgotten by one of the rulers of Equestria. I was hoping Starswirl had told you two about me,” the pony said.
Luna remembered back during her training by Starswirl the Bearded. It was over a thousand years ago. It finally dawned on her who the pony is and it horrified her.
“Azrael...,” Luna said.
“DING! DING! DING! WE HAVE A WINNER!” Azrael said. “I knew that old bag of pony flesh wouldn't forget about me.”
“I take it your contract is up then?”
“Right again Princess!” Azrael sneers at the Princess of the Night. “It's been so long, but I'm finally free of my contract. So guess what I get to do now? Go back to my old job! However I do require a host...”
“If you want me as the host, I will stop you Azrael!”
“Oh, you're not my host. I have someone else in mind,” Azrael said. Then an image of a unicorn filly appeared within a blue whirlpool. The filly was all white with a purple and pink mane and tail, and green eyes. Luna's eyes went wide as she knew the filly.
“No... Not her... Not Sweetie Belle...”
Azrael grinned evilly. It's razor sharp teeth showing. “So, you know this filly? Well, I guess I have my next destination. If you try to stop me in the dream world. I swear I will make you beg for a quick death.”
“You cannot stop me Azrael! No pony can stop me! I will hunt you down in whatever dream you've entered! I will make you go back to escorting souls to the afterlife for judgment!”
“I knew you'd say that,” Azrael said. "That is why I need some kind of leverage. What better leverage is there than your own soul?”
Before Luna could speak, she felt the life being sucked from her body. Her soul was being forced out of her body by Azrael's magic. Before long, it was over. Luna's soul now belonged to Azrael, and Luna's actual self's fate was unknown at best.
–-
Back in reality, Celestia was sound asleep. But she couldn't help the feeling that something was wrong. Really wrong... It was at that time that member of Luna's Royal Night Guard burst into Celestia's personal quarters and woke the Princess of the Sun up.
“Your Higness! I'm sorry for waking you at this late hour! But it is Princess Luna!”
“This had better be good Sergeant!” Celestia replied not hearing the last of the Sergeant's report.
“It is Your Highness! Princess Luna is in a coma!”
Celestia gasped in shock at the news. She couldn't believe something like this. And that it had happened to her sister of all ponies...