Herds. In a world inhabited by magical ponies, that's really not too surprising of a thing... unless that herd consists of four living, breathing goddesses and yourself.
Twilight has an interesting conversation with Sparkler when she finds her sitting on a park bench all by herself, looking very depressed. To Twilight's dismay, SHE'S the reason Sparkler is so upset.
With the onset of the windigo curse, Commander Hurricane and the other tribal leaders leave in search of new lands. They aren't the only ones to face challenges, as the tribes inch closer and closer to ripping each other apart with each day.
The pegasi that founded Equestria have a dark past, a past steeped in war and a fight for the survival of their very race, and one that Commander Hurricane played a key role in.