This story is made by Hollydove, and it is about Equestria's struggles against an unknown menace of the night.
Luna's point of view.
I, Princess Luna, and my sister, Princess Celestia, stood on the biggest of the triplet balconies.. It was painted half dark blue with white markings and half white with pale yellow markings. The door led into the hall that interconnected the our rooms.
Celestia flared her wings. Her yellow magic aura glowed, with a blinding white outline around the horn, and the sun slowly set, disappearing into the horizon. My horn glowed my blue aura, with the same outline around it. The moon rose above the horizon, and the ponies playing outside galloped inside.
It was long after my time as Nightmare Moon, and long after Discord had been reformed. Princess Twilight was happy with her friends in Ponyville, and Princess Cadance was happy at her home, the Crystal Empire. But problems arise, even in times of peace.
When Celestia went to her room, I felt something calling to me inside my thoughts.
Princess Luna, said the voice, I am so happy to finally meet you at last. You remember me, right? The Nightmare Energy that you released into this world after Nightmare Moon was banished?
"Darksmog," I answered. "Wait - how does Celestia not know?"
Because when the Elements of Harmony defeated Nightmare Moon, they trapped me inside Tartarus - all but a small bit of me trapped in your head. I've been drawing Negative Energy from your nightmares, all your bad thoughts, Darksmog answered. Only now I have the power to speak with you. I will never escape - the Tree of Harmony is making sure of that. But I can unleash my wrath with you. Bear with me, this will hurt.
I yelled, but only in my head. After the transformation tingling went away, I was indigo-colored, and my mane was the darkest of blues. I was wearing golden armor like I had as Nightmare Moon, but I had bat wings and weird claws instead of hooves. Two fangs were sticking out, and my eyes were bright red. I took flight, and bit the nearest pony I saw - Shining Armor, captain of the Royal t.
I quickly saw what my Nightbat bite could do. It drained energy, and it caused ponies to be sick. I saw him turn pale blueish, and he sprouted blood-filled blisters. His eyes went like a blind pony's eyes. Then I saw him undergoing transformation. If I kept biting ponies, than I would have a whole army!
What's happening? I wondered.
When you bite someone, they become a Batminion, Darksmog answered. As you and your Batminions bite more ponies, they will become a Batminion, but if you bite them in light, they will get sick, shrivel up, and slowly dehydrate to death. Remember, you will become normal in the day, except for your fangs.
Yes, I will remember, I thought with an evil smile.