Onderon was a jungle world located within the Inner Rim. During the Clone Wars, it aligned itself with the Confederacy of Independent Systems; in the Separatist Senate, Onderon was represented by Senator Mina Bonteri and later by her son, Lux Bonteri. When Supreme Chancellor Sheev Palpatine turned the Republic into the Galactic Empire and declared himself as the Emperor, the planet was taken over by the Imperials. This gave the rebirth of the Onderon rebels once more, now led by Saw Gerrera.
In its earliest ages of civilization, Onderon was a world marked with savage jungles that were filled with dangerous creatures. To survive, the primitive human inhabitants of the planet protected themselves behind the walls of fortified settlements. Over time, these settlements grew to become enormous walled cities, including the planet's capital, Iziz.
In the years after the Invasion of Naboo, the political idealist Count Dooku spread political turmoil on the world along with a host of others across the galaxy such as Sullust. During the time of the Clone Wars, the planet's monarch King Sanjay Rash allied Onderon with the Confederacy of Independent Systems. However, many Onderonians refused to recognize the legitimacy of Sanjay's rule, as they preferred the neutral stance championed by former monarch Ramsis Dundup. This opposition led to the formation of the Onderon rebels, a group of freedom-fighters organized by Jedi Knight Anakin Skywalker.
With the help of the Ahsoka Tano, Obi Wan Kenobi, Anakin Skywalker and Captain Rex, they promised to help the rebels secretly by training them to fight against the Confederancy droid army as well as giving them supplies. First forced to hide out in the jungles of Onderon, the rebels trained how to take down droids and tanks with the help of EMP grenades. However, in the midst of the training the training camp was attacked by a droid battalion. The rebels with the help of the Jedi were able to take down the droids with relative ease. Now that they were ready for combat, they were ready to infiltrate the capital city of Iziz.
There, the rebels continued fighting against droids, destroying few droid patrols and checkpoints. These actions soon were noted by king Sanjay Rash, who ordered the former king Dendup to stop the attacks. It soon became noted that he wasn't in charge of the rebel attacks, which seemed to frustrate Rash even more.
At some point the rebels were able to take out the droids' main power supply by hijacking one of the CIS AAT tanks and taking out the power grid, after a small battle between the droids and them. These actions became notified by Count Dooku, who was displeased with Rash not being able to take care of the insurgents. Rash blamed the droids for this and asked for reinforcements, but instead, the Count sent a super tactical droid named Kalani to win where Rash had failed.
With the power supply down, the rebels were able to take down more and more droids quite easily with little resistance. Some time later the leader of the resistance, Steela Gererra, was able to send a message to the people of Iziz that their true king, Dendup, was silenced by King Rash and that would take back their city.
This message concerned Rash that he eventually ordered the executiom of the former king. The news made their way back to the rebellion. Steela's brother, Saw Gererra decided to rescue the former king, but was captured by the droids. He was then brought inside the palace for interrogation personally overseen by Kalani and General Tandin. Before Kalani tortured Saw to death, he was stopped by Tandin who saw the droid's tactics ineffective against stopping the rebels. However, the droid saw that Tandin pitied Gererra. After some time Gererra and the general spoke with each other, speaking how Saw had become a terrorist, and how Tandin choce to stay free by going under the Separatists' rule. Saw said however that he was no terrorist, but a freedom fighter trying to free the people of Onderon from Separatist occupation. This made the general think of his actions.
Later that same day was the former king Ramsis Dendup's execution. The rebels had planned to free the king during the execution, in which they almost succeeded, but were apprehended by droid reinforcements. Witnessed by general Tandin, he gathered the royal guard and freed the imprisoned rebels. The resistance fighters were able to escape with the general holding the king Rash as hostage, but he was going to get shot by the droids pointing guns at him. As hope seemed lost, Ahsoka Tano jumped out of the crowd watching the execution and force pushed the droids away, stunning them. The two were able to escape from the droids with the people stopping the droids going after them. Now that the king Dendup was freed, the people were more rebellious against the droids and Rash's rule.
The rebels made their way to distant mountains, where they established a base of operations. Back in the city Lux Bonteri and Ahsoka Tano showed their last message, now by the king Ramsis Dendup. This message finally started mass riots across the capital, causing chaos in the city. Meanwhile droid scouts were able to locate the rebels' hideout somewhere in the eastern mountains. Because of the riots going on in the city, most of the droids were needed to control the outbreaks. As Rash seemed helpless, Kalani assured with the death of the king Dendup and the rebellion, fear would bring order back to the people. He also sent additional reinforcements to assist the droid army, Droid Gunships.
As the droid army made their way to the mountains, the rebels at first were able to take out most of the droids very easily. But just as the gunships arrived, the rebels were outgunned and outmatched very quickly. The gunships were equipped with mini rocket launchers and shields, that were immune to blaster fire. The rebels seemed to be lost and Ahsoka was order to retreat back to Coruscant by Obi-Wan Kenobi. Back on Coruscant Anakin Skywalker didn't accept the fact that the Republic shouldn't just ignore helping the rebels, so he took the control to his hands. He travelled to Florumm to make a deal with Hondo Ohnaka and hired him to deliver rocket launchers to the rebels on Onderon, illegally.
Back on Onderon the rebels were getting heavy losses by the new gunships, but the fight took a new turn when Hondo and couple of his pirates brought them the rocket launchers Anakin ordered. The rebels were able to take down the gunships with the help of the new weapons. Back in the base, commando droids were able to discover the king's hideout and almost killed him, but were destroyed by Steela in time. At the same time, Saw and the rebels blew up the remaining two gunships, one of which crashed at the side of the mountain the king was on. As a result of the crash, the mountain broke down, leaving Steela hanging on the edge. Lux came to help but was knocked down as well, but was rescued by Ahsoka Tano. The crashed droid gunship wasn't destroyed and shot a blast at Tano's shoulder, interrupting her force grip, dropping Steela to her death.
With Steela's sacrifice, the rebels were able to defeat the droid army once and for all. Back in the city King Rash was desperate, demanding for more reinforcements. Count Dooku wasn't so pleased to the news, who ordered Kalani to regroup the remaining forces and bring them back to Agamar. The droid general finally executed Rash as a result of his failure.
With the Separatist army gone, Onderon was finally freed and joined the Galactic Republic.
However, the peace didn't last too long as the Republic was formed into the first Galactic Empire at the end of the Clone Wars. Onderon presumably was first of the planets to fall under Imperial rule, due to being located in the inner rim. With the Empire control of the planet, the rule similar how it was back in the war, was back again.
The Imperial rule caused insurgency groups to rise once more, led by Saw Gererra, who also was a leading member of the resistance back in the Clone Wars. ISB Agent Kallus' was tasked to take down the rebels. His first Stormtrooper unit was ambushed by a lasat mercenary who was working for Saw Gererra. Kallus and the unit was caught in an explosion that knocked the ISB agent away. The lasat slowly walked through the smoke and fire and killed every single imperial, even the ones injured in the blast that were unable to defend themselves.
- Star Wars: Galactic Defense (Mentioned only)
- Star Wars: The Clone Wars – "A War on Two Fronts" (First appearance)
- Star Wars: The Clone Wars – "Front Runners"
- Star Wars: The Clone Wars – "The Soft War"
- Star Wars: The Clone Wars – "Tipping Points"
- Star Wars: The Clone Wars – "The Gathering" (Appears in flashback(s))
- Star Wars: The Clone Wars – "Sabotage" (Appears on data screen only)
- Tarkin (Mentioned only)
- Star Wars Rebels – "The Honorable Ones" (Mentioned only)
- Aftermath (Mentioned only)