Luna opened up her laptop. She loaded up Hoofle Docs and created a document titled "The Truth". She sighed as she started typing. The text she wrote said the following: Today will be the day I tell you the truth. It might shock you, and you might hate me once I tell you, but I am a killer.
It all started 1500 years ago. My younger sister Helia was born. I was jealous of her the instant she came into this world. I was cursed to carry the responsibility of night on my shoulder, while she got the responsibility of day. Everyone loved her, for the light and happiness she brought, but they all hated me for the gloom and darkness I brought.
One day she decided that she make day longer than night for part of the year, and I lost it. I ran into the kitchen of the house we shared. I took a couple cyanide and crushed them into dust. I took the dust and mixed it with chocolate icing. I then proceeded to bake a cake for her, and put the poisoned icing on it.
I put the cake on a plate and carried it down the hall to her room. I looked at her, and with a hint of a growl in my voice, I said, "Hey Helia, I made you a cake in gratitude for giving me a bit of time off." I set it on her desk and she started to eat. Once every last crumb was gone, I broke into laughter. She fell onto the ground and, with every last ounce of breath she had, she gasped, "You... sick... bastard..." She stopped moving.
I looked down at her lifeless corpse. Her yellow body and orange mane turned colorless, and as her sun cutie mark faded away, I sat down. I had won. I started laughing. I laughed for hours on end.
I realize now that I let my jealousy overcome me. But I didn't care then. I was to happy to realize it. I looked out the window, and a sudden rage overcame me. The sun was gone. My original plan was to take the sun as my own after she died. Then I realized that she was the sun. And I just put out the fire.
I went into a raging fit. I caused chaos around Equestria to make everyone suffer the same pain that I had. I killed other's families, caused a 200 year famine, and swept disease upon disease across the globe. It grew tiresome. I made myself immortal. I hadn't slept for centuries. I then created Discord, who soon became my best friend. He would cause chaos and I would watch. In our free time we'd have in-depth conversations. I realized that for the first time since Helia died, I was happy. I realized how much I missed happiness and light.
I went back to Helia's body, and took it to my room. I proceeded to make a clone of her. I found the part of her brain that let her control the sun. I threw the tiny chunk of flesh into a vial filled with dna, different coloring genes and made Celestia. She rose out of a cloud of smoke the reaction made. I looked out the windowand saw light. The plants grew back, and ponies came out of their homes with smiles on their faces. I ran towards my sister and hugged her. I whispered to myself, "I'm happy you're back."
She saved the document, and emailed it to Celestia, with a tag on the end that read: I'm sorry I didn't tell you sooner.
Celestia came into the room an hour later and hugged Luna. She whispered to her, "It's okay."