Sombra waited for a full hour after the sister’s left to even dare move. He had barely been able to contain his excitement for the past few months and now that the day had arrived he could scarcely sit still. When the queen had threatened her sister with not leaving he felt his heart in his throat; he didn’t know if it was himself or Celestia that was more relieved to find she was only putting on airs.
After what seemed to be an eternity Sombra concluded that Luna was far enough away that she could not sense what he was about to do. He let out a dark chuckle and began his work. His horn took on a black magical aura and green smoke leaked out of his eyes, a telltale sign of the school of magic that Sombra had developed in secret. The beam hit the crystal above the throne and turned it black in an instant. The darkness seemed to take on a life of its own as it spread throughout the throne room and on to the rest of the castle.
Sombra felt the dark tendrils of his magic as they raced out to the outer reaches of the city where they drew up a wall imprisoning the city before its residents knew what had happened. The virulent darkness spread from the throne room and the new wall to the rest of the city and as dawn rose on the crystal empire, where there was once a dazzling jewel standing out from the landscape there was a dark blot that seemed drink up all the light that came by it.
Within minutes the first of his new slaves came to the throne room with their concerns. Where they expected to find an obedient steward serving his absent queen they instead found a king, dark and terrible in his armor. All the ponies cowered in a corner at the sight of him and he let them stay for a time. When most of the city had gathered in front of his throne Sombra addressed the crowd.
“You are well versed in the manners and proceedings of court; you are not arrogant unicorns from Equestria. Why do you not bow before your king?”
At once ponies found their courage and charged the throne shouting Sombra down for his betrayal. He laughed darkly. The fools had played right into his hooves and now he had an excuse to demonstrate his terrible magic. The few unicorns in the crowd were fast to react and had a shield in place but their magic was nothing against his. The shield fell as quickly as it had been conjured.
The black beam struck several ponies. Sombra felt panic rise for a moment when he saw that no physical harm had befallen the ponies. They stood in shock for a moment before the spell took hold. One wept for his mother, another cursed hers, a particularly smart one pleaded for the mercy of death.
The crowd watched in horror as the ponies were deconstructed from the inside out. The spell was designed to fragment the ponies and subjugate the weakest fragment and it worked with a terrible beauty. Sombra let the minutes stretch by as the once defiant ponies in front of him were reduced to sniveling wretches and their cries died to a wordless moan of mercy. Then one by one they were filled with darkness. They got up and bowed to him as if nothing had happened and assembled in front of the throne facing outward.
Finally Sombra saw fit to address the horrified crowd, “kneel,” he commanded. One by one the once proud crystal ponies and the few others in their midst kneeled to the new king.