So I was thinking about unicorns a lot a while back and now I've got at least 4 subspecies inhabiting the headworld and now you're going to get to learn about them!
Most common and what most centaurs think of when you say unicorn is the above, the Common or Dwarf unicorn! They were made almost entirely from goats and they remain essentially goats with a single horn, usually fairly straight and curving backwards, but there are many different varieties as they are treasured as fine pets and decent livestock, kept for their company, milk, and meat just like goats. Thankfully their attitudes are closer to mini horses than goats, adding to their favor as pets, but they're still quite mischievous as opposed to their more capricious goat cousins.
Next most common, but still fairly rare, is the "True" unicorn! These ethereal beasts are known bastards! Long, fine boned, strong and tough as nails despite their delicate looks these war mounts are visually the closest to a traditional unicorn other than the sparse mane and tail - thought to be owed to the clear base of the breed being Akhal Teke horses. Unfortunately their attitudes do not match their beauty as they are through and through war horses. Used almost exclusively in the eastern kingdom as nobles and knights mounts in their neverending skirmish wars these beasts bond to exactly ONE person at a time and everyone else is liable to be bitten at best, run through with that horn at worst. An absolute nightmare to stablehands throughout their range, they are finicky and aggressive to horses and humans alike making them difficult to keep. They are shockingly intelligent and KNOW how to use that horn to its greatest effect, leading to the nickname of 'Fencers' Even in their native range they're not super common due to the aformentioned difficulties in keeping them and the fact that they frequently prefer to fight one another than breed.
Most rare and least understood is the 'Heraldic' unicorn, these stately but wild creatures are as beloved as they are dangerous. They tend to just appear out of the wilds to those they choose as riders, and are well known for their loyalty and gentle dispositions in times of peace and as deadly war mounts in battle, leading to an enormous amount of legends around them. They are the mounts of kings and explorers, nobles and common adventurers, most who wind up with one of these creatures live extraordinary lives. They also require a significant amount of protein in their diets, and if it is not provided they will acquire it.
Last, and also kind of least is the 'Wild' unicorns. These are clearly the remnants of some rogue genetics that pops up in primarily wild horse herds for some reason. They are just horses that grow a horn, usually of a roughly spiraling nature. It is fairly fragile, and so not very useful but they're still favored as a novelty mount to many and often passed off as one of their more unique cousins to the uninformed. Because of the edge the horn gives them in herd dynamics, if a wild unicorn makes it to adulthood with the horn intact, this can often form pocket herds of unicorns as the gene briefly proliferates- but it never seems to last more than a few generations.
