The Battle of Ylesia took place at Ylesia, a planet, in 0 BBY. It pitted the Alliance to Restore the Republic against the t'landa Til and their Cult of The One and The All, which had its base of operations on that very world.
To secure funding for their operations, and to free prisoners with the hope of gaining new recruits from the liberated pilgrims, the Alliance to Restore the Republic devised a plan to assault Ylesia, a planet dedicated to drug processing, with the aim of seizing spice. Because Ylesia was under the control of the Besadii Hutt kajidic, the Alliance secured assistance from Jabba Desilijic Tiure, whose clan was locked in a bitter rivalry with the Besadii. Jabba dispatched assassins to eliminate the t'landa til priests before the invasion, intending to prevent their empathic "Exultations" from hindering the attackers.
However, the Besadii had received support from Black Sun, including the Nova Force mercenary regiment and a ground-based turbolaser stationed in Colony One – a detail unknown to Jabba.
Bria Tharen led the Alliance's Red Hand Squadron in the attack, supported by a smuggler fleet provided by Jabba. This fleet included well-known smugglers such as Han Solo, Lando Calrissian, and Chewbacca. The Squadron was divided into nine units, each targeting a major colony on Ylesia. During the assault, the turbolaser destroyed at least one unit, led by Jalus Nebl aboard the Dream of Freedom. In addition, Jarik Solo was killed during a brief space battle.
Despite this, the Rebels swiftly overwhelmed the Nova Force units, who surrendered. Before destroying the spice-processing plants and storage warehouses, Red Hand Squadron plundered a significant amount of spice and credits from Ylesia. Simultaneously, Tharen and Solo ventured into the treasure chamber of the High Priest Teroenza, where Teroenza ambushed them. Before he could shoot Han, Boba Fett killed the t'landa Til, having been hired by Durga Besadii Tai on a Priority Bounty to avenge the deaths of Aruk Besadii Aora and Kibbick. However, Tharen betrayed the smugglers who assisted in the Colony One raid, seizing their portion of the spice and treasure to bolster the Alliance's finances, acting on misinterpreted instructions from her superiors within the Alliance.