(Stupid-late night headcannon-ish bullshit rambling ahead! If you want to skip it, skip it, but don’t go inquiring about something in the comments unless you’ve read!)
 
Long before recorded pony time, there lived a race of ponies who had, over time, been bred apart from the ponies of the Crystal Empire we know today. It was a peaceful kingdom: Fair skinned ponies were abundant, guards non-existent, and magical talent bloomed as the unicorn gene made its way through the lineage of once earth ponies, and soon, pegasi blood mixed with the gene pool as well, creating a kingdom for all in equality.
 
Soon though, ponies began to envy one another. Earth Pony lineages who had not recieved either tribe’s genes hated the Unicorn’s affinity for magic, and the Pegasi for flight. Unicorns strived to acquire flying and strength spells to keep up with the Earth Ponies and Pegasi, and the Pegasi, most envious of all, began to sabotage crops and sugar-cane fields to dampen the earth ponys’ strength, and the Unicorn’s ability to record tomes of magic.
 
The silent feuds came to a boil, and the kingdom fell into chaos. Word reached the nearby Unicorn Tribe kingdom of their neighbor’s folly, and devised a plan with the other tribes. Their finest wizards were sent forward, and a curse was cast upon the land. So they all shall have desired their wings and horns, so shall they have at a price: the love their kind was so commonly given would be replaced by disgust and fear, leaving them searching forever for what they’d lost. Coats darkened, eyes glowed, manes and tails hardened and shrunk like their hearts. Horns sharpened, and wings’ feathers molted and shed into glistening wings. The greed ate away at the Kingdom’s citizen’s extremities, leaving gaps in their hooves, to remind them always of the pain they’d brought upon themselves.