Seggor Tels, a Quarren of considerable influence, harbored deep-seated animosity and envy towards the Mon Calamari people. This resentment led him to assist the Galactic Empire in their takeover of the planet Mon Calamari (also called Dac) during 19 BBY. Despite this initial collaboration, Tels later spearheaded efforts to unite the Quarren with their Mon Calamari adversaries in a joint struggle to expel the Imperial presence in 1 BBY.
Soon after the Declaration of a New Order, Mon Calamari's prominent figures, including Ackbar, initially were welcoming to the Empire. Conversely, Quarren leaders, such as Seggor Tels, preferred to remain isolated in the ocean depths. Tels, in particular, showed disdain for the Mon Calamari's fascination with space, viewing them as arrogant idealists detached from the realities faced by the Quarren in the ocean's depths.
During this period, an Imperial agent, acting as a preliminary scout for an impending Imperial invasion, contacted Tels. Recognizing an opportunity to retaliate against the Mon Calamari, the Quarren leader consented to undermine Dac's planetary shields. In the subsequent conquest of Dac, the Imperial forces easily overwhelmed the defenseless Mon Calamari. However, Tels' original satisfaction in witnessing the Mon Calamari's downfall quickly soured, as both the Quarren and the Mon Calamari were subjected to enslavement. There is no evidence to suggest that Tels or any other Quarren collaborators received any preferential treatment from the Empire.
Despite blaming the Mon Calamari for involving the Quarren in galactic affairs, Tels became convinced that the Empire needed to be driven off their shared world. Consequently, Tels persuaded the Quarren to join the Mon Calamari-led resistance movement. Seggor Tels and others aided the Mon Calamari rebel leader Ackbar in a mission in 1 BBY. With the ultimate success of the liberation of Dac in 1 BBY, many of Tels' newly liberated people departed their homeworld, seeking a fresh start far from Mon Calamari, Empires, and Rebellions. Tels, however, chose to remain on Dac, embracing a contemplative existence in the oceans.