Augustus with his fellow Jaffa.
Augustus was the cybernetic First Prime of the Goa'uld Mars, his living component being a mar'kak, who served his master on the graveyard planet Kar'tek. He led the group of cyborg Jaffa who were chasing Etahy and his Volca family and discovered the lost chaapa'ai in doing so. The group took Aemon, Etahy's son, back to Mars with the information about the chaapa'ai but soon returned both to capture the rest of the Volca and to secure the Stargate with a much larger contingent of Jaffa.
Augustus, Mars' First Prime.
However, upon their return, they found not only Etahy but also SG-1 of the Tau'ri. The two groups fought briefly but SG-1 was soon captured through sheer numbers. Augustus once again came before Mars, bringing with him the first human hosts which Mars had seen since his banishment to the planet. When Teal'c acted up against his captors on the way to the palace Augustus explained to him that, if he had not wore the mark of Apophis, then he would have ripped the symbiote from his stomach and crushed it before him. Augustus then entrusted Ganthas to lead them the last distance to the palace. When they got to the palace, it was Augustus who introduced their presence to Mars.
It was not long before Augustus showed his loyalty to Mars, as SG-1 attacked the Jaffa and stole their staff weapons hoping to slay the Goa'uld and his cyborg followers. Augustus was hit by a blast from O'Neill's staff weapon before hitting him across the head, knocking him to the floor, while Mars used his Kara kesh to send the rest of the team flying. Although Augustus wished to slay O'Neill for his insolence, Mars stopped him and instead simply sent Teal'c to the Colosseum while arranging to use O'Neill as a host.
Augustus somehow managed to escape when Daniel Jackson and Etahy returned to free their friends, returning with Patrician after SG-1 had left so as to save Mars from death. Ordering Patrician to take Mars' symbiote into his mar'kak body, he ensured that his god would still live after the supposedly fatal blow which had earlier been delivered by Etahy. (SG1: "Fall of Rome 1")