These swallow-like minions strive to collect energy as offerings to their master. When a large group of them converge, it causes a tornado that builds their nest. It is in this nest that they perform the final preparations for their gift. They live for their master. If they lose their master they are supposed to disappear, but it seems they continue to serve somewhere in a different form.
The witch’s swallow-like minions, who are collecting magic energy as offerings for their master.
Several of them can gather together and whip up strong tornadoes, with which they collect nearby objects into a nest. They then store magic energy in the nests, where they make preparations to offer it to the witch.
Their goal is to save their master in every way possible.Upon losing their master, they would ordinarily become unable to fulfill their role and vanish, but it seems that they’re still hard at work in a different form somewhere else.