Gaia watched the small unicorn with interest, she could sense madness in him. Madness in a mortal was quite odd, but she had seen it before. Unfortunately it meant he was meant to ascend and join the Mad One's against the Shadows. She knew Discord still hadn't made peace with his madness so she was reluctant to let the chaotic spirit teach him the Arts.
Venus, the Embodiment of her own Madness, was singing a song to the sleeping pony. "Have faith in yourself and beware your darker self, He'll lie and cheat just so he can beat, you in your own game." She flew circles around his head, "Embrace the Madness and you will see, the great power that lives inside you and me." She smiled, Venus had a nasty habit of switching between calm and serene and wild and screaming. "Soooommmbra~! This way~!" She zoomed off into the maze giggling.
Gaia took flight, soaring far overhead. The Maze of the Mind, the first test to the mastery of the Arts. Getting lost in it would make you permanently brain dead. Gaia thought back to when her mind broke and Thanatos helped guide her through her own maze. She was familiar with the dangers. "Live damn you." She whispered. "Thanatos won't forgive me if I let his first apprentice die horribly."
She watched him charge into the maze, horn lit and ready. She began to hum and the maze sprung to life, spewing out his greatest fears. "This will be your life's most painful moment, but you must understand what you have done little Godling." She spoke in the Labyrinth's voice. She could feel the maze agreeing with her. "Embracing what you've done is the first step to being free."
Sombra looked around, surprised. "I've done nothing wrong. I was being used."
The Labyrinth chuckled. "It was still your hatred that fueled Him, your hooves that broke the bones of innocents, your magic that committed those deeds. You are just as at fault as the False God who took control of your soul." Gaia leaned back and watched. It was all the maze would allow of her. "I'm going to break you down, then your mentor will rebuild you. There are three tests you must undergo, I am the first. Once you complete the next two you will be truly reformed."
"Why should I trust you?" Sombra growled. "The last time there was ominous voice speaking to me I ended up killing my best friend."
"Don't forget her husband and about two hundred other Crystal ponies." The Labyrinth chuckled, again. "I know everything you've ever done Sombra. I am made to manifest all of your greatest fears and deepest desires. The difference between me and... Him, is that I will not force you to do anything. Everything you do in here, you do yourself. I will present you with tests but I will not tell you they are a test. I will find your true nature... if it kills you."
"Well that's not ominous at all." Sombra grumbled.
"Begin." A manticore leaped out of the shadows and launched itself at the unicorn. Gaia smiled and manifested some popcorn kernels. Venus was humming to herself and staring blankly at the fight. The Labyrinth had gone silent and was watching Sombra with curiosity. "Are you sure he is the one?"
Gaia popped a handful of kernels with her flames. "Body of a unicorn, heart of a pegasus. Those Valkyries are enamored with him. Except for Skuld. She can't see his future and it pisses her off."
"I await the day they return to us." The Labyrinth spoke with reverence to the Great Spirits. "Skuld cannot see anyone's future at present."
"And Urd can't weave the past. It doesn't change anything. Urd and Skuld weaved everything up to the Great battle. But when it came to him, none could see what would be. It makes him dangerous, a loose cannon." She eyed the popcorn kernels that lay unpopped at the bottom.
"Say Gaia." Venus chirped. "Didn't Thanatos ask us a favor?"
She sighed and set down her popcorn. "Don't kill him while I'm gone, or else Ange will destroy you and every trace of your existence."
"I wouldn't dream of it." The Labyrinth sighed. "Don't die again." Gaia and Venus disappeared in a ball of flame.
Sombra felt his training kick in as he dodged to the side of the manticore's wild swipe. He skidded on his hooves and charged up a dark magic spell. Night black crystals burst from the ground and impaled the beast through the heart. Suddenly the manticore transformed into a familiar pegasus. She wailed loudly. "Why!?! You were my brother! Why would you do this to us!?!"
"Onyx." He breathed as the pegasus went limp. "NO!" He destroyed the crystal and ran to her side. "Wake up, please." He nuzzled her side. "You're the Final Storm! You faced Dragons and Giants! You made the first Sonic Storm in Millennia and took the first step to making the Crystal Ponies embrace us. You can't die, not at my hoof." He opened his eyes and saw his reflection in a puddle of her blood.
He saw a curved red horn and slitted eyes. Purple tears poured out of the corrupted green sclera. It was completely different from Staff Sergeant Sombra, it was King Sombra. The reflection grinned, revealing sharp fangs. "One down, three to go."
His hooves moved without his consent. He began to trot through the ruined throne room, flinging the massive doors open with his magic. In his head he began to repeat the same mantra over and over. It's just a test. It's just a test. It's just a test. It's just a test. It's just a test. It's just a test. His body spoke. "Come on out Greenhoof, I know you're there. Are content to sit back as I murder the rest of your family?"
"Raugh!!!" The Green Crystal Pony leaped out off the shadows. "Traitor!" The pony knocked him over, slamming his hooves into his chest, denting the steel armor he wore. Suddenly he was back in the labyrinth battling a hydra.
Sombra created a Sword in his magic and sliced off one of the lunging heads. "It's just a test." He said. "It's just a test. It's just a test. It's just a test. It's just a test."
After a bit he slammed the blade into the Hydras heart and it died with a final screech. "Very good Sombra. You managed to ignore the illusions... after shedding a few tears." One of the walls of the labyrinth opened. "Continue."