Chapter twelve: Sombra And Discord.
Sombra is another one of the scientists attempts to recreate the human to pony transformations.
This created a dark pony that managed to develop magic of fear and shadows…. But Sombra could not talk properly thus preferred to not really talk at all if he could.
Sombra found the way into the crystal's underground and actually created the empire for his own home…..But he wasn't alone as greedy unicorns joined him then he wanted to rule them….. So the events seen in the show happened.
Deemed evil by his ways the princesses defeated him to end the suffering of those under his rule.
Discord is actually an animal mutation that also ended up being part human. He was mixed with other animals thus allowing him magic over chaos as seen on the show. His first time ruling was when he was learning to control his powers after the explosion then the princesses defeated him and brought harmony back. He ends up listening to Fluttershy not just because he learned the magic of friendship but he is also parts of different animals and that also helped him as his inner animal felt an attraction to her as a friend because she understands animals.
The way he managed to make the ponies Discorded was actually a mixture of his magic and a mind control spell but since he can't cast spells the same as unicorns his mind control is in the form of hypnotizing eyes.