Umbara, known as the "Shadow World" due to the lack of sunlight on its surface, was a planet located within the Expansion Region. Resting within the occluding Ghost Nebula, Umbara was cut off from the rest of the galaxy. This resulted in the development of advanced technologies that far exceed the galactic standard by the native Umbarans. During the initial stages of the Clone Wars, Umbara was a member of the Galactic Republic, though it would defect to the Confederacy of Independent Systems following the assassination of senator Mee Deechi, who had represented the planet within the Galactic Senate. In response, the Grand Army of the Republic would launch a successful invasion of the Shadow People's homeworld.
During this invasion Anakin Skywalker was called back to Coruscant at the chancellors request. Pong Krell took over the 501st in Anakin's stead. later Rex realized Krell a Jedi of all people, was working for the separatists and a random clone kills Krell after Krell orders the clones to kill one another.
- Star Wars: The Clone Wars – "Darkness on Umbara" (First appearance)
- Star Wars: The Clone Wars – "The General"
- Star Wars: The Clone Wars – "Plan of Dissent"
- Star Wars: The Clone Wars – "Carnage of Krell"
- Star Wars: The Clone Wars – "The Gathering" (Appears in flashback(s))
- Star Wars: The Clone Wars – "An Old Friend" (Appears in flashback(s))
- (First identified as Shadow World)
- Ultimate Star Wars
- Star Wars: Absolutely Everything You Need to Know
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