Windigos

Windigos are a race of ghostly creatures with a horse-like appearance. They are winter spirits that feed off of the fighting and hatred between others and create blizzards and freezing weather.

They always roam in a group of three. They are believed to be much weaker if separated. 

They do not show signs of sentience, they are merely malice driven spirits.

The Everfree Grifix have tales regarding them, but those tales sound different from the tales pony-kind has...

Note: windigo shaped sphirix are ALLOWED. That is because windigos are not considered sentient species, and only their appearance is horse-like.