What if Queen Chrysalis is a corrupted breezie? Once the queen of the breezies, she was tired of relying on something as supercilious as breeze to get her home, and started to research spells to make her large, powerful. She preached the idea that breezies could be something more, something powerful, and gained followers. Others were not so pleased, and after a terrible civil war, she and the breezies who followed her were pushed out of the portal. But by then, Chrysalis already knew her transformation spell - or at least she though she did. It ended up mutating her body and her peoples, yet they did not care, or at least, fearing Chrysalis’ wrath, did not mention their unhappiness. Finally, they were a force to be reckoned with.
 
TL;DR: Chrysalis and her changeling army are mutated breezies.

Oh Christ, the origin of fucking breezies.