- "Another armed occupation is not a free Ryloth. How long before I am fighting you, Master Jedi?"
- ―Cham Syndulla, to Mace Windu
Ryloth was a planet in the Ryloth system of the Outer Rim Territories, and the homeworld of the Twi'lek species. Its terrain varied, filled with jungles, mesas, valleys, and volcanoes, and had an atmosphere breathable for Twi'leks and humans alike. A forest covered its equator, filled with dangerous predators. Given the varied and dangerous terrain, Twi'leks lived in caves underground where it was safer.
In the years preceding the Clone Wars, Count Dooku secretly backed coups on Ryloth as part of larger political attempts to seed discontent in the galaxy's Outer Systems during the Separatist Crisis. Upon the declaration of war between the Confederacy of Independent Systems and the Galactic Republic, Ryloth was invaded by the Separatist Droid Army, however was ultimately repelled by the Republic, several Jedi, including Anakin Skywalker, Ahsoka Tano, Obi-Wan Kenobi, Mace Windu and Ima-Gun Di. As well as the Twi'lek Resistance, the latter of which was led by freedom fighter Cham Syndulla.
After the end of the Clone Wars in 19 BBY, Ryloth officially became a protectorate of the Galactic Empire. While classed as free and independent, its title did not reflect reality. Many isolated settlements did not even know of the Empire's existence until they were raided and their populations forced into slave labor. As consequence, the former Free Ryloth movement initially formed to fight the Separatists during the Clone Wars instigated a new rebellion against the Empire.
By 14 BBY, the planet was overseen by Moff Delian Mors who lived on a moon orbiting the planet. That same year, Darth Sidious and Lord Vader became trapped on the planet after the destruction of the Imperial-class Star Destroyer Perilous over the planet in an attempt to assassinate the Empire's political leadership, a move designed by Cham Syndulla's reorganized Free Ryloth movement. The attempt failed to kill the Emperor and his apprentice.
By roughly 3 BBY, Imperial TIE bombers based on an orbiting Quasar Fire-class cruiser carrier were used to bomb Ryloth. Cham and the Ryloth resistance wanted to destroy the carrier in order to demonstrate their strength. However, his daughter Hera Syndulla, who had become the leader of the Spectres, a rebel cell, disagreed with her father's plan and convinced him and his companions Numa and Gobi Glie to steal the ship for the Phoenix Cell; which desperately needed a carrier to house its starfighter squadron. During the mission, the two rebel cells also managed to destroy an Arquitens-class command cruiser which boosted the morale of the Ryloth resistance.
In 2 BBY, the Chiss Grand Admiral Thrawn was dispatched by the Empire to deal with the Free Ryloth movement. By studying Twi'lek art, culture, history, and philosophy, Thrawn was able to devise successful counterinsurgency tactics that led to the capture of Tann Province. He also captured the Syndulla residence and forced Cham Syndulla to flee.
- "Today Rinnrivin's cartel presents a danger to Ryloth's future, and to free trade in our part of the galaxy. Tomorrow, however, it could threaten the rule of law in the New Republic itself, as the Hutts did in both the Old Republic and the Empire. There, I ask for the Senate to investigate the reach and influence of Rinnrivin DI's cartel and to take the actions necessary to restore order, on behalf of the Twi'leks of Ryloth—but for the benefit of us all. [sic]"
- ―Yendor addressing the New Republic's Galactic Senate
In the year 5 ABY, the Galactic Empire abandoned their garrisons on Ryloth. After the planet regained its independence, the rebel fighter Yendor became the planet's ambassador to the New Republic, the government that had been established by the Alliance to Restore the Republic.
Following the Galactic Concordance, Ryloth did not join the New Republic and instead opted to remained a sovereign and independent world from both the Populists and the Centrists political factions. About six years before the destruction of the Hosnian system, Ryloth's economy and independence came under threat from the Nikto crime lord Rinnrivin Di's cartel, which had become a major spice dealer and smuggling group. Rinnrivin's cartel exacted a heavy toll on Ryloth's offworld shipping due to sporadically-enforced New Republic financial regulations, infrequent patrols of the shipping lanes, and rampant bickering within the Galactic Senate. Emissary Yendor traveled to the Galactic Senate on Hosnian Prime to raise his planet's plight to the Senate.
In response, Senators Leia Organa and Ransolm Casterfo traveled to Bastatha and Ryloth to investigate Rinnrivin's syndicate. Over the course of their investigation, the two senators discovered that a mysterious entity was channeling funds to Rinnrivin's cartel through a militia group called the Amaxine warriors as part of a conspiracy to destabilize the New Republic. While visiting the Ryloth archives, Leia and her entourage discovered that Rinnrivin was formerly a lowly spice dealer who had rapidly risen to become the leader of a powerful criminal cartel.