Jolian was a cyborg whose organic component was a Mar'kak who was once a member of the former Goa'uld System Lord Mars' senate. However, upon seeing Mars' actions when SG-1 were brought before him, the senate decided to act against Mars, and help SG-1. It was only when Teal'c was entered into the colosseum, and after he had defeated both the Minotaur and Medusa, that the senate decided to act. While Teal'c was having trouble defeating the Hydra, the members of the senate picked up staff weapons and fired on the beast, killing it and freeing Teal'c.
Jolian being shot dead with a staff weapon.
They then took Teal'c and a number of Volca out of the colosseum to a predetermined rendezvous point off of the streets. It was there that they spoke with Teal'c and tried to decide how they could overthrow Mars. Before they could form a plan, however, Mars' Jaffa found them, killing Jolian with a staff blast and capturing the remainder of the group. (SG1: "Fall of Rome 1")