Changeling Civil War

"After the Belkan Grey Men freed Queen Chrysalis from the statue and when Thorax was framed for a terrorist attack by these Gerasecian feds, It seems that there could be only one type of changeling pony left to rule in superiority, be it the original, black, holed changelings that feed on love... or the metamorphosed changelings that love nature and cherish love on each other. Whatever, my money's on Thorax. And Queen Chrysalis? Well, she'll have to pay for that."

--Su Ji-Hoon, The Return of Queen Chrysalis

The Changeling Civil War is the civil war between Queen Chrysalis and Thorax that it would be located in Equestria.

It would be happened in during the USRAC War when Belkan Grey Men restored her from her statue since Thorax has been framed that it would be caused Changelings became against each other due to join either Queen Chrysalis or Thorax