The Battle of Umbara, also known as the Umbaran Campaign, was a battle that took place during the Clone Wars on the planet Umbara. It was also the event during which the treason of Jedi General Pong Krell was revealed, whose ultimate goal was recognition by Count Dooku to become his new apprentice.
The Separatists started to tighten their grip over vital and isolated supply routes. Following the death of Umbara’s senator, Mee Deechi by Lolo Purs, the Umbarans withdrew from the Republic and committed their militia to the Confederacy of Independent Systems. The Republic then sent Jedi Master Pong Krell, Jedi Knight Anakin Skywalker, and Jedi Council members Obi-Wan Kenobi and Saesee Tiin to retake Umbara with their troops.
Krell was a recognized war hero, but was known for his exceptionally high rates of troop casualties compared to other Jedi. Unbeknownst to anyone else, Krell had had a vision of the Jedi Order‘s fall and the rise of a new order, leading him to fall to the dark side and begin sabotaging campaigns he fought in with the aim of attracting the attention of Separatist leader Count Dooku, who he hoped would reward him by making him his new Sith apprentice.
Though the Umbaran militia was strong and possessed technology more powerful than much of the Republic’s own weapons, the Separatists deployed a sizeable fleet to the system to assist the militia in defending their home and supplying arms. As a result, the Separatist fleet established a large blockade around the planet.