There are many stories about the origin of the Hareppi: that they were birds that flew too close to the storms; that they were once just like humans but altered by strange science; that they are wicked spirits come to punish honest men and women. While nobody is sure what they were, everyone knows what they are now, for they are a constant worry for fragment dwellers. They are strange birdlike creatures, seemingly at least as intelligent as humans but chaotic and wild in behaviour and emotion. They constantly flit from fragment to fragment, pausing only long enough to exhaust whatever resources are readily available.

They have elaborate birthing rituals, where eggs soon to hatch are carried up into storms along with all the members of its parent's close families. These birthing flocks fly deep into the Storm, so that the egg is saturated with the power of the Storm. Thus when it hatches the fledgling already has great command of the power of the storm, but has also been altered by the storms to behave in a much more chaotic and wild fashion. As a result when the Hareppi arrive on a fragment the result is extremely unpredictable; human generosity could be rewarded or exploited, and even hostility from fragment inhabitants could impress the Hareppi enough for them to leave a boon. On the other hand, all too often they leave behind a fragment devastated by their Storm magic and stripped of all resources the Hareppi could take.