The Quarren Isolation League was a group that maintained its own soldiers and held the conviction that the Quarren should not be governed by the Mon Calamari monarchy. This organization was under the command of the Quarren chieftain Nossor Ri, who was of the opinion that King Yos Kolina's successor, Prince Lee-Char, was not old enough to take over his throne. The League gained support from Separatist ambassador Riff Tamson, who was actually Kolina's secret assassin, and who aimed to use the League as a tool to seize control of Mon Cala.
Tamson initiated an attack against the Mon Calamari, supported by aqua droids, Trident-class ships, and subsequently Hydroid Medusas. Despite their initial success against the Mon Calamari Guard, their Republic and Jedi comrades, along with the Gungan Grand Army, Lee-Char managed to persuade Nossor Ri to betray Tamson. This shift occurred after the Karkarodon revealed that he had made an agreement with Dooku to gain control of the planet. Following Tamson's death, Lee-Char was crowned as king, enjoying the support of both the Mon Calamari and the Quarren.