Board Thread:Spoilers!/@comment-27060727-20160929050506/@comment-26116863-20161015150700

Maybe they're playing with the word, change, and don't literally mean changlings, as in human children swapped with fairies. Maybe the result of some change, or transformation. Maybe this is the episode where a number of citizens get split personalities, the good sides get locked up or supresses, depending on whether they seperate, and the evil ones run amuck.

Just speculation.