'Twas a result of an aspect of our star—and universe—named "dynamis". Strong emotions create an impact on their environs, and in this instance, despair brought forth abominations.

The influence of dynamis is typically not quite so noticeable, however the flow of aether had been disrupted and that resulted in the strengthening of dynamis.

[ There's... a lot more to it, but he thinks that's a sufficient explanation. ]

We managed to defeat the source of such despair, you are correct.