Based on the changeling concepts of Siansaar

(By request, links to specific relevant parts of lore, though I encourage you to look at his art in general.)
Changeling Concept: The Hive
Changeling Concept: Husks (this may not end up having much relevance)
Changeling Concept: Reproduction
Changeling Concept: Enslaver

Mesmera is a queen whose egg had been stolen by an enslaver. The enslaver, being fed up with her egg's love consumption and gestation time, decides her egg is a dud and discards it, and she hatches alone.

Cover art by xcinnamon-twistx