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// Empty Sky 
// Story: Gloom and Doom 
// by casualbrony10 
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Luna reacted instantly, her instincts and ancient training taking over. She shot a rapid fire burst from her horn as she leaped to the side. Her blasts  were powerful spells meant to immobilize and cause intense, but non lethal pain; she wouldn't kill if she could help it and she wanted to interrogate this monster after she subdued it. Her attacks struck perfectly, one in the head, another in the chest, and a third in the right hind leg. Even if it could withstand a blow to head and chest, the leg shot should temporarily cripple it. Gloom landed in a heap and tumbled into the space between her guards, who immediately surrounded him with their spears drawn. Luna smiled, but her expression turned to surprise as the creature instantly melted into a thick, dark liquid which spread around her guards' feet. In a split second the liquid shot up and solidified into large tendrils. The lunar guard barely had time to shout before they were pinned to the floor by the grasping structures. Luna spread her wings and flew forward to aid them but Gloom's head suddenly rose out of the pool and his cold eyes met hers. A vast, all consuming consciousness invaded her mind and reached for her memories.
"Mind magic!" her thoughts screamed. Drawing upon her strength of will, she focused on an image of the moon until it filled her consciousness. Gloom could see only the moon as he searched for anything he could use against her. Frustrated, Gloom pounded at the image, attempting a brute force method. Any observers would have seen the two combatants simply staring at each other motionless except for slight twitches. Mind magic had little to do with physical power, and only a small amount of magic was required to enter another's mind, will is the deciding factor. Luna managed to push Gloom back enough to cast a spell, a quick flash from her horn as a distraction. He blinked his eyes and Luna took the opportunity. She flew up and sent two attacks at once, a paralyzing spell and a mental attack. She could take no chances with this creature. Luna had thought mind magic to be a lost art, Celestia and her had decided to ban its practice after the incident with King Sombra 1000 years ago. The only known living beings who knew of it and could still use it are Celestia, Discord, and herself. Twilight, Cadence, and Chrysalis had displayed basic potential but they still needed spells to control other's minds so it was not true mind magic. The most interesting instance of a pony developing it entirely on their own was Fluttershy and her "stare". That was the first step toward mastery of mind magic, using eye contact as a channel, the next was the ability to reach out with the mind alone, then one could read thoughts as well as exert control. Fluttershy is a unique case of incredible natural talent, she likely didn't even know what her stare truly was, mind magic took extensive discipline to master and required a tiny amount of magical power. All unicorns had the capacity for it, but it was rare among pegasi and unheard of for earth ponies. With it the weakest magical being could become extremely dangerous. It is considered dark magic, for nothing was as violating as invading the thoughts of others, one could wipe identities away, destroy the consciousness or sanity, break somepony in the worst possible way. Luna had not used it since her time as the nightmare; she had vowed not to use it unless faced with an enemy that could.
Luna's mental attack was a technique that had made her fearsome as Nightnmare Moon. She stabbed at Gloom's mind with terrible nightmares and fear. She had no idea what the creature was afraid of so she targeted basic instinctive fears of loss, pain, and death. Her nightmares entered Gloom's mind ready to consume it, and dispersed harmlessly. Gloom shielded himself from the paralysis spell and looked up at her.
"That was dark princess, you have so many shadows in you. Do you really consider yourself a good pony? If you are, you'd be haunted by how much of monster you are." Gloom's voice was a hiss. Luna was shocked, only Discord could throw something like that off so casually, it's as if it didn't care about fear. What is this creature? Luna looked towards her guards, who were still laying on the floor although the tendrils were gone. They were all curled up in random positions and sobbing to themselves. Their eyes dripped with strange black tears and stared without seeing. They were muttering words between sobs and she could just barely here some.
"I failed, I failed my one duty, my purpose."
"No! I'm not useless, I'm not!"
"It's my fault, it's my fault, it's my fault, it's my....."
"But I tried to protect her. I really tried."
"Was this fear, Sombra's power, her power?" Luna thought, "No, it was something deeper, darker." Her thoughts were cut short as Gloom continued his mental assault, coupled with a physical attack of grasping tendrils. Luna focused on the moon again but her concentration failed when a tendril squirted a thick black sludge onto her wing and stuck it in mid flap. She tumbled to the ground where more tendrils rose and held her. She struggled and to her credit, the stone floor beneath her cracked, but it was no use. Still struggling against Gloom's mind, Luna struck out in desperation, no longer caring if she killed this monster, and lightning blasted Gloom. The bolt seared his hide and even blew off some of it, revealing a gruesome skeleton beneath. Gloom didn't even flinch, his telepathic attack increased in intensity as he focused solely on Luna, numb to any damage to his body. 
Luna's vision darkened, then cleared quickly. She found herself in the old throne room at the Castle of the Two Sisters. She stood in front of her throne and Celestia was in front of her, not 20 feet away. Had she been teleported to safety by her sister?
"Sister, thank goodness! There is a monster in Canterlot, we have to get back and..." Luna realized that her mouth made no noise, it didn't even move.
"Not another step!" She heard herself say, "Did you really think I'd sit idly by while they all basked in your 'precious light'?" What? She didn't say that. It was then that she realized that that the castle was not in ruins, it looked as it did that fateful night a thousand years ago. She was in a memory, her least favorite one. Gloom's voice echoed in her head as she relived her transformation into the Nightmare.
"You really suppressed this one. You almost think of it as another life, but that is wrong, this was you, there is no denying that."
No! She had put that behind her, the elements had cured her of her bitterness and she could see now that Celestia had always loved her and so had her subjects. More images and experiences passed before her, each so vivid that she could feel the moonrock beneath her hooves as she stared forlornly at the Earth, smell the scent of apples at the summer sun celebration as she triumphantly stepped out on stage to terrify the ponies below, hear the voice of Twilight Sparkle as she said that the elements were right there. She could feel exactly what she thought at each of those moments, the rage, the hate, the fear, the sorrow, the pain, the terrible things she wanted to do to all the poor defenseless ponies out of spite and jealousy. The twisted pleasure she had felt at seeing them scream in fear. She saw herself, a terrifying, fanged monster with glowing blue eyes, laughing insanely as the world fell to everlasting darkness. Gloom spoke the entire time, every word cutting into her psyche.
"Do you really think that the elements simply made you good? That thing is still in you, it was always in you because it is you. Your sister may have forgiven you, but then again it took 1000 years. But it shouldn't have been her forgiveness that you sought, what of all those ponies who feared you for the rest of their lives? Who saw you in their nightmares and passed your story on to their children. They lived and died fearing you and always thought of you as a monster. They must have been pretty traumatized for that fear to live on as 'Nightmare Night'. The mere mention of Nightmare Moon or the Pony of Shadows makes their descendants hysterical. It took just a few ponies sleeping through the night and worshiping your sister to turn you into that. Worse, you never changed on your own, the elements of harmony had to force you to return to good. You never chose good, but you did choose evil, that is the real you, what you are now is a brainwashed thrall of harmony who has tricked herself into thinking she is better now. You can't even do your job right! I got from some of the ponies of Canterlot that you slept through the Changeling invasion, and you were useless against Discord, Sombra, the plundervines, Tirek, and basically anything that could have proven your dedication to protecting Equestria. You have put so much evil into the world and given very little good. Teaching a filly to face her fears? Telling another not to give in to jealousy? Drops in the ocean Luna. You deserve to be miserable!"
Everything this monster said was true, she was not worthy of her crown, of her sister, of Equestria. Tears fell from Luna's eyes, at first clear, but then slowly turning black as they flowed into Gloom's body. What could she ever do to make up for her crimes? Nothing seemed to matter anymore as Luna lay on the floor, her heart utterly broken, and Gloom looming over her catatonic body. Gloom's tendrils released Luna as physical restraint was no longer necessary, her body was limp and she stared off into the distance, her eyes glazed over. She was trapped within her own mind, lost in a vast chasm of despair and misery. 
Gloom eyes glowed as he tested his newest battery. The damage Luna had caused healed immediately and the power he had spent began to replenish. Unlike Tirek, Gloom did not rip all the magic out of ponies, instead he put them into a kind of stasis/coma where they would be so overwhelmed with misery that they wouldn't care about anything anymore. While they were in this state Gloom forged a link through which he could draw a steady stream of energy, always taking at the same rate the ponies' bodies could recover. Gloom could also tap into any memories the ponies possessed and augment his mental powers with their suffering. After all, who could withstand having their mind assaulted with the anguish of a thousand ponies? The ponies would not die while Gloom was using them, a minuscule amount of his magic would keep them breathing, their hearts beating, and their bodies nourished. It was a complicated system, but horrifying to behold. 
Gloom took from Luna the location of Celestia's bedchamber and quietly left the sobbing ponies to their fates. As he made his way through the gardens he looked up at the night sky. A thought occurred to him, now that the princess of night belonged to him, could he make the heavens themselves cry? He raised a claw to the sky and a bank of dark cloud-like shadows appeared. They spread across the sky and one by one the stars winked out until the moon was surrounded. The clouds swallowed the moon and thickened until they looked like a single, smooth surface. They were higher up than any pegasus could fly and no light penetrated them as they spread across Equestria. For all intents and purposes, the sky was empty. It began to rain.