The pale and ghostly Umbarans are an extremely high tech species who have decided that the Separatists are a more worthy group to follow than the Republic. At one time represented in the Galactic Republic by the devious Mee Deechi, Umbara seceded from the Republic and joined the Separatist cause. Their advanced weaponry proved a great challenge to the clone troopers tasked with conquering Umbara.
Umbara, known as the "Shadow World" due to the rays of its sun never completely reaching its surface, is perpetually dark. The native wildlife have adapted to survive in such gloom, making the planet perpetually dangerous. Umbara was once part of the Galactic Republic, represented in the Senate by Senator Mee Deechi. Later in the Clone Wars, the planet's loyalty wavered and the natives of Umbara allied themselves with the Separatists, bringing their extremely advanced technology to the Separatist Alliance.
At the time of their introduction, the Republic clone troopers represented the future of galactic warfare. Far superior to battle droids, the clone troopers formed the backbone of the Republic's new military that waged war against the forces of the Confederacy of Independent Systems. So symbolic were they of the times, the galaxy-wide conflict that saw their debut took its name from their ranks: the Clone Wars.
The Confederacy of Independent Systems, also known as the Separatist Alliance, was a collection of star systems and corporate titans that left the Republic and fought for independence against the Republic’s clone armies and Jedi Knights. The charismatic former Jedi Count Dooku was the Alliance’s political leader, while its military power came from credits and assets donated by powerful galactic trade groups. No one suspected that the Alliance was actually a tool of Darth Sidious, who had engineered the Clone Wars as part of a Sith plot to rule the galaxy.