Following the Huk War, the Yam'rii desecrated the burial grounds of the Kaleesh on the planet Oben, prompting Kaleesh warlord Qymaen jai Sheelal to return from working for the InterGalactic Banking Clan to again lead the kolkpravis. The IBC sabotaged Sheelal's shuttle, nearly killing him and killing seven of the eight Izvoshra, elite warriors who protected him and carried out his will. Qymaen was later resurrected as the Separatist cyborg General Grievous; who played a pivotal role in the Clone Wars.
The sole surviving Izvoshra, a tyrant of Kalee's western hemisphere named Bentilais san Sk'ar, rallied the kolkpravis and led the slaughter of the Yam'rii on Oben, where he subsequently moved his people. Following the Clone Wars, the Kaleesh were targeted by Palpatine's new Galactic Empire due to their ties to the Separatist movement. For nearly a decade, the Kaleesh Resistance under Bentilais held out until they were finally routed by Captain Thrawn on Oben.
Thrawn, who was usually able to study his adversaries' art and devise a strategy to defeat them from there, was unable to comprehend Kaleesh artworks, and so levelled Oben with his Star Destroyers; inflicting heavy casualties and bringing an end to the insurrection. Sk'ar survived the deadly bombardment by the Imperial fleet. However, he bore no ill will against his enemy, as he admired their superior technology and tactics and felt his people had died with honor.
When approached by Imperial occupation forces under Captain Rel Bentin, General Sk'ar offered his life or his services. Bentin, intimidated by the towering figure of Sk'ar, brought the Kaleesh before Emperor Palpatine. Despite the Empire's xenophobia towards non-humans, the Emperor was impressed enough by the Kaleesh's courage and potential to accept Sk'ar into the ranks of his Imperial armies.
Thus, Sk'ar went down in galactic history as one of the few non-humans to reach an important position within the humanocentric Galactic Empire besides Grand Admiral Thrawn and the Procurator of Justice Hethrir. With an Imperial strike force under his command, Sk'ar embarked on a campaign across the Jahilid Drift, conquering several worlds and making a name for himself in the Imperial Military. Meanwhile, the kolkpravis was taken over by a female Kaleesh believed to be the second coming of Grievous's dead soulmate, Ronderu lij Kummar.