- "I know where it is. The planet is called Thule. Thousands of years ago it was an ancient Sith stronghold. Ulic fought there during the war. That's where the Dark Reaper is buried."
- ―Anakin Skywalker
Thule was a semi-arid planet known for its rich savannas, continually bombarded by lightning storms, but Thule was also a hidden Sith stronghold. The rocky outcroppings which broke the plains were charred black from being hit by lightning. This charred rock later served as a form of sustenance for unusual, bioluminescent moss that made the rocks glow with an eerie light.
During the era of the Sith Empire, Thule played host to a Sith stealth regiment drawn to the world by its strong connection to the dark side and its isolated location. In the aftermath of the Great Hyperspace War, a small group of Sith survivors fled to the world, bolstering its population of Sith special forces. These Sith remained on Thule for generations, waiting to take their revenge on the Jedi and the Republic. They established a military dictatorship, ruled by an oligarchy of eight generals.
Around 1000 BBY, Lord Kaan's Brotherhood of Darkness encountered the Chiss in the Unknown Regions and brought a legion of them to colonize Thule. Their descendants would spread out to the wider galaxy, although their species was still unknown to many. 
In 22 BBY, Count Dooku went to Thule to revive the Dark Reaper in an attempt to destroy the Galactic Republic during the Clone Wars. A planetary shield enveloped the planet Thule, projected by the small moon Sivvi orbiting it. An attack led by the Republic resulted in the Battle of Thule and the destruction of the Dark Reaper.
Behind the scenesEdit
Star Wars: Complete Locations places Thule in the Expansion Region, in relative proximity to Shili, whereas other sources confirm its location in the Outer Rim Territories. Due to a last minute change at Lucas Licensing, Thule was also incorrectly placed in the Inner Rim in Inside the Worlds of Star Wars: Attack of the Clones.
- Inside the Worlds of Star Wars: Attack of the Clones
- Geonosis and the Outer Rim Worlds
- The New Essential Chronology
- Star Wars: Complete Locations
- Jedi vs. Sith: The Essential Guide to the Force
- The Complete Star Wars Encyclopedia
- The Essential Atlas
- The Unknown Regions
- Book of Sith: Secrets from the Dark Side