Onderon

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. A grouping of societal outcasts ended up living within Onderon's jungles instead of the protected cities. Within those jungles, they used the rupings as mounts.

According to the quasi-historical Qel-Droma Epics, a Sith Translation Talisman allowed its wearer to instantly understand the Force-imbued writings of Sith scrolls and spellbooks. Krath leader Satal Keto found one on Onderon and reproduced it to train his fellow Krath. It was considered one of the most prized relics sought by Qel-Droma Epics scholars.

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 Inner Rim was of strategic interest to the Confederacy, so the Separatist-backed monarch King Sanjay Rash allied Onderon with the Confederacy of Independent Systems after pro-Separatist coup and Separatist invasion deposed monarch Ramsis Dendup. However, many Onderonians refused to recognize the legitimacy of Rash's rule, as they preferred the neutral stance championed by Dendup. This opposition led to the formation of the Onderon rebels, a group of freedom-fighters organized by Jedi Knight Anakin Skywalker.

Led by Skywalker, a contingent from the Galactic Republic, including Ahsoka Tano, Obi-Wan Kenobi, and Captain Rex, helped secretly train and arm the rebels to fight against the Separatist Droid Army. Forced to hide out in the jungles of Onderon, the rebels trained to learn 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 defeat the droids with relative ease. Now battle-tested, the rebels felt ready to infiltrate Iziz.

Within Iziz, the rebels continued fighting against droids, covertly and systematically destroying droid patrols and checkpoints. Thinking these actions were led by the deposed Dendup, Rash ordered the former king to stop the attacks. It soon became known that Dendup was not in charge of the rebel attacks, frustrating Rash.

Continuing the siege, the rebels were able to take out the droids' main power supply by hijacking one of the droid battle tanks, knocking out the power grid after a skirmish. These actions were brought to the attention of Dooku, who was displeased with Rash for not being able to quell the insurgents. Rash blamed the droids for this and asked for reinforcements. In response, the Count sent General Kalani, a super tactical droid, 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 Gerrera, was able to send a message to the people of Iziz that their true king, Dendup, was silenced by Rash and that they would take back their city.

This message concerned Rash, so he ordered the execution of the former king. This news made its way back to the insurgency. Steela's brother, Saw Gerrera, decided to rescue the former king without help but was captured by the droids. He was then brought inside the palace for interrogation overseen by Kalani and General Akenathen Tandin. Kalani intended to torture Saw to death but was stopped short by Tandin, who believed the droid's tactics ineffective against stopping the rebels. However, the droid believed that Tandin merely pitied Gerrera. Saw and the general spoke with each other, the general explaining how Gerrera was viewed as a terrorist, and how Tandin chose to stay free by going under the Separatists' rule. Saw viewed himself not as a terrorist, but as a freedom fighter trying to free his people from Separatist occupation.

At the public execution of Dendup, the rebels attempted to free the king, but they were apprehended by droid reinforcements. Tandin, a witness to the rebels' capture, gathered the royal guard and freed the imprisoned rebels. The resistance fighters were able to escape while the general held Rash as hostage. The general himself was held at gunpoint, so 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 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 Tano showed the insurgency's last message, now by Dendup. This message finally instigated mass action across the capital, causing riots and chaos in the city. Meanwhile droid scouts were able to locate the rebels' hideout in the eastern mountains. As Rash seemed helpless, Kalani assured him that with the death of both Dendup and the rebellion, fear would bring order back to the people. He also sent additional reinforcements to assist the droid army in the form of HMP droid gunships.

As the droid army made their way to the mountains, the rebels at first were able to eliminate most of the droids very easily, but as the gunships arrived, the rebels were outgunned and outmatched very quickly. The battle seemed to lost and Tano was ordered to retreat back to Coruscant by Kenobi, reasoning sometimes people need to fight their own battles. Back on Coruscant, Skywalker did not accept the fact that the Republic should just ignore helping the rebels, so he traveled to Florrum to make a deal with Hondo Ohnaka, hiring him to illegally deliver rocket launchers to the rebels on Onderon.

During the battle, the rebels were dealing with heavy casualties from the new gunships, but the fight took a new turn when Ohnaka and a couple of his pirates brought them the rocket launchers Skywalker ordered. The rebels were able to take down the gunships with the help of the new weapons. Back in the base, commando droids discovered the King's hideout and almost killed him, but they 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. Bonteri came to help but was knocked down as well. Bonteri was rescued by Tano. With Bonteri safe, Tano focused her attention on Steela, and levitated Steela from the edge of the cliff. However, the crashed droid gunship was still marginally operational however and shot a blast at Tano's shoulder, interrupting her Force grip on Steela who dropped and fell to her death.

With Steela's sacrifice, the rebels rallied to defeat the droid army once and for all. Back in the city Rash was desperate, demanding more reinforcements from Dooku. Dooku however was not pleased with his lack of control, and he ordered Kalani to regroup the remaining forces and bring them back to Agamar. The droid general executed Rash as a result of his failure, and retreated from Onderon.

With the Separatist army gone, Onderon was finally freed and joined the Galactic Republic. However, Onderon was under siege, prior to the Battle of Coruscant.

The peace bought through sacrifice during the Clone Wars was not long-lasting. The Republic reformed into the first Galactic Empire and it annexed Onderon. An insurgency rose up against Imperial rule, led once again by Saw Gerrera.

Shortly after Order 66, Imperial Admiral and Governor Tarkin tested the loyalty of Clone Force 99, also known as the "Bad Batch," on a mission to Onderon. Tarkin told the elite clones that they needed to eliminate a band of "Separatist insurgents" on Onderon. However, when the squad arrived, they came upon a group of people, former Republic fighters and refugees that included children and elderly individuals. The Bad Batch's leader, Hunter, disobeyed orders by refusing to fire upon refugees and families. The group, led by Saw Gerrera, surrounded the Bad Batch and captured them. Gerrera made an offer for the clones to join his resistance group, but the Bad Batch chose instead to return to Kamino. Ultimately, however, Gerrera declared the planet to be a lost cause and retreated from it.

Later, a new squad led by Crosshair, who had left the Clone Force 99 due to their defection from the Empire, arrived to finish the mission to eliminate Saw and his militia. However, Saw was already gone, and the only ones left were some militia members and some civilians. All were killed, including the Elite Squad Trooper ES-01, who had refused to eliminate the civilians, which was seen as treason by Crosshair.

Later on in the Imperial Era, Imperial Security Bureau Agent Alexsandr Kallus and his first stormtrooper platoon was tasked with bringing peace and security to the troubled world. Kallus and his unit were then ambushed by a Lasat mercenary who worked for Saw, and Kallus and his unit were caught in an explosion. Kallus was knocked out of the way and the mercenary slowly walked through the smoke and fire and killed every Imperial except for Kallus; including the ones injured in the blast and unable to defend themselves.