Avernio Three

Avernio Three was a planet located in the Unknown Regions of the galaxy. At some point before roughly 6000 BBY, the planet was chosen by the Iokath species as one of the testing sites for their weapons and Avernio Three's unique civilization was assaulted with the destructive force of Iokath weaponry.

Behind the scenes
Avernio Three is briefly mentioned in Star Wars: The Old Republic: Knights of the Eternal Throne Chapter IV: Where Dreams Die.