Kintac was the lieutenant to Na'onak (in actuality, the Goa'uld System Lord Apophis) while on the moon Netu, demanding that other denizens of the prison-planet kneel before Na'onak.
He later served as Apophis' First Prime when it was revealed that Na'onak was in fact Apophis risen from the dead, and was dispatched to retrieve the prisoners (SG-1 and Martouf) whom Apophis wished to personally interrogate in order to learn more about the other races that SG-1 had befriended as well as knowledge about the Tok'ra.
Kintac also administered the Blood of Sokar to these individuals, often through force, which initiated hallucinations in an effort to get SG-1 team members Colonel Jack O'Neill, Major Samantha Carter and Dr. Daniel Jackson to tell Apophis everything.
Unfortunately and despite his good work and strong, undying loyalty to Apophis, Kintac's tenure as Apophis' First Prime proved to be very short-lived as the Tok'ra soon caused the moon's core to explode, ultimately resulting in the entire moon erupting as well.
While Apophis escaped to safety, he later abandoned Kintac and the other inhabitants that had rallied to Apophis's cause in hope of freedom, Apophis himself presumably feeling that Kintac had truly outlived his usefulness and that Kintac and the other prisoners had been nothing but a means to an end.
As such, unaware of the fact that his master had abandoned him, Kintac was one of the many people left on the planet who died when the moon was eventually destroyed. (SG1: "Jolinar's Memories", "The Devil You Know")