'She's such a Tanith'
"I tried to get her to stop beating herself up about her mistake, but she was much too Tanith to listen."
Tanith was a young and treacherous Goa'uld
Tanith murdered Teal'c's lover and infiltrated the Tok'ra as a spy. What Tanith did not know was that the Tok'ra were aware of his duplicity, and used him to funnel false information to the Goa'uld.
While still incubating within the Jaffa priestess Shau'nac, Tanith communicated with her and convinced her that he wished to turn against his Goa'uld heritage and join the Tok'ra. But after coming to maturity and taking a volunteer named Hebron (whose people were decimated by the Goa'uld) as his host, Tanith killed her.
He lived among the Tok'ra as a spy for Apophis, and entered the service of Anubis after escaping a Tok'ra prison cell (and a death sentence). Tanith was soft-spoken and self-controlled, and took great pleasure in cooly taunting his enemies -- especially Teal'c, who he associated with Shau'nac as a traitor to the Goa'uld. But eventually, Teal'c realized his long goal of revenge: he is presumed dead after Teal'c shot down an Al'kesh that Tanith was piloting (with a direct hit to the cockpit). It had been less than two years since he took his first host.
Colonel Jack O'Neill: Yeah, it's a sweet ride. Little rusty, but it's got a lotta zip.
Tanith: How, exactly, did a Gou'ald mothership come into your possession?
Colonel Jack O'Neill: It was kind of a trade deal.
Tanith: How so?
Colonel Jack O'Neill: Cronus gave us his ship and he... got what was coming to him.