An ancient race of separatist Jaffa who, five millennia ago, escaped rule of the Goa'uld (specifically Ishkur). Branded as traitors, they went into the galaxy to search for Kheb, and ultimately enlightenment, in the hopes that their souls would be cleansed. Instead, they found and established the Sodan homeworld (Earth designation P9G-844).
For five thousand years the Sodan have thrived, worshiping the Ancients while raiding Goa'uld symbiote transports as necessary to sustain themselves. Circa 1905 (on Earth) Lord Haikon took the seat as leader and overseer of the Sodan and the preservation of their way of life.
Since their discovery the Sodan have been criticized for knowing about the existence of the Goa'uld but not helping their distant cousins in their oppressors' defeat. Despite the need for strong leadership in the forming Free Jaffa Nation the Sodan do not concern themselves with the condition of the rest of the Jaffa race.
Approximately one hundred years after Haikon took power the Sodan homeworld was paid a visit by a Prior who offered enlightenment through worship of the Ori and the guidelines through Origin. Haikon realized that his people had spent thousands of years paying homage to gods who never gave the people anything in return. However, the Ori were apparently willing to share the secrets of enlightenment. Haikon lead the Sodan public in Prostration toward the Ori -- though a small dissident group continued the Sodan way of life, hoping to restore it to the majority.
After they were convinced to help SG-1 against the Prior the Sodan faced a terrible retribution. One of their own, Volnek, was infected by a dark ailment that turned him into a vicious killing machine. He turned on the Sodan village, killing everyone and leaving only Haikon barely alive.
Babylon - SG-1 and SG-22 visit P9G-844 in the hopes of finding the mythical Sodan.
The Fourth Horseman, Part 1 - Colonel Mitchell leads a team back to the Sodan homeworld, where they are quickly captured.
The Fourth Horseman, Part 2 - The Sodan's allegiance to the Ori is broken after they refuse to destroy simple farmers who refused to submit to Origin.
Arthur's Mantle - SG-1 finds the Sodan village slaughtered by the ailing Volnek, with Haikon alone left fighting for his life.