Total dominance

Equestria had fallen, the ponies, and all other creatures from the world of Equestria had been totally conquered by a force out of this world, the human empire, at first their magic was difficult to deal with, but after enough study, they managed to neutralize it, making them unable to fight back. Even the magic of friendship was useless against the power of their technology; all unicorns had their horns locked with a nullifying ring that stopped them from using magic, and all pegasus had straps on their wings to forbid them from flying, they didn't need free use of those for their new roles as manual laborers, power batteries as they discovered their magic was a great source of energy and straight up breeding slaves for the dominating humans.

Each pony now had at least 1 human master that they had to obey loyally and without question; they would be severely punished.