The Sith wyrm was a massive creature that lived on the fourth moon of Yavin in large subterranean lairs.
The ancient Massassi worshiped the beast as a god until it was killed by Exar Kun a millennia later, who did so to impress the spirit of Freedon Nadd. Unknown to either the Massassi shaman Zythmnr or Exar Kun, Nadd was engineering this conflict to manipulate Kun; Kun could only defeat it by using the power of a Sith amulet and committing himself more fully to the dark side of the Force. It was learned later that the creature was originally an infant exogorth that had attached itself to Sadow's battleship. Failing to tame the creature and seeing no other use for it, Sadow opted to alchemize it into the first Sith wyrm.
- Tales of the Jedi – Dark Lords of the Sith 4 (First appearance)
- Timeline 10: The Exar Kun War (Appears in hologram)
- The Dark Side Sourcebook
- Knights of the Old Republic Campaign Guide
- The Complete Star Wars Encyclopedia
- Jedi Academy Training Manual
- Book of Sith: Secrets from the Dark Side