Shan'auc came to believe she had convinced her larval Goa'uld symbiote to foreswear his birthright and oppose the Goa'uld. Shan'auc had once been very close with Teal'c, probably before he married Drey'auc.
Shan'auc had come to believe in Teal'c's cause, that the Goa'uld were false gods and the Jaffa should be free. While in a dangerously deep state of kelno'reem meditation, she broke with Goa'uld law and attempted to communicate with her symbiote. Eventually, she believed she had turned it from its genetically evil ways and convinced it to join the Tok'ra resistance movement. (SG1: "Crossroads")
This section requires expansion
When it became time for the creature to take a host, she journeyed to Earth for help in making contact. She also wished to re-acquaint herself with Teal'c, who had recently been, for lack of a better translation, divorced. Once the Tok'ra provided a new larval symbiote to sustain her life, Shan'auc and Teal'c planned to return to Chulak to help other Jaffa learn to commune with their symbiotes. Her symbiote, Tanith, took possession of the volunteer host Hebron.
But he soon revealed to Shan'auc that he had been manipulating her in order to infiltrate the Tok'ra, and killed her by crushing her new Prim'ta which also resulted in Shan'auc suffering a long, agonizing death. However it was later revealed the Tok'ra had actually been aware of this deception all along, intending to use Tanith as an unwitting dupe to pass false information to the System Lords until they were ready to strike. (SG1: "Crossroads")
Teal'c vowed to avenge the loss of Shan'auc and wait for the perfect time when Tanith, believing he had successfully infiltrated the Tok'ra, would not be watching. It was more than a year later that he finally caught up with the Goa'uld and killed him, finally avenging the death of his beloved Shan'auc. (SG1: "48 Hours")
When Teal'c was badly injured, and forced to share his symbiote with Bra'tac, he hallucinated that he was a member of the fire brigade. In this hallucination, a version of Shan'auc (called Shauna) was his wife. (SG1: "The Changeling")
- In an alternate timeline accidentally created by SG-1, Shan'auc likewise became a temple priestess. Teal'c told Daniel Jackson that he would have otherwise proposed to her as "she was brave and beautiful and wise beyond her years." At some point prior to 2005, Amaunet took Shan'auc as her host when her previous host was injured beyond the symbiote's ability to repair while she was visiting to Chulak. (SG1: "Moebius Squared")