SpiritSteeds - breed idea

I'm going to use these guys in my comic, but I'm wondering if anyone would be interested if these were an harpg breed, or maybe rp breed, since they live in world with no humans.

The breed is based on my old spirit unicorns made for game Howrse:
     

Breed characteristics:
- the horses are divided by four elements - water, fire, earth, air
- they can be any build, but earth and fire horses tends to have heavier build than water or air
- their horn is not attached to the head
- horn always look like element horse posses
- mane and tail is always having form of thick mist and resembles element of the horse
- the horses lives in herds and are called by the place where they live 
- horses may have accesories characteristic for its element
- horses can learn to use elemental magic