10 Stargate Characters Who Vanished Without A Trace
4. Sarah Gardner
Sarah Gardner was an old colleague and flame of Daniel Jackson's, who most unfortunately ran afoul of the Goa'uld System Lord Osiris. She was quickly taken as a host, proceeding to become a major thorn in SG-1's side over the following years. Although Osiris himself was male, he was unafraid to use his female host to further his goals.
He quickly established himself as an underling of the returning System Lord Anubis, a Goa'uld so evil that even the rest of the System Lords expelled him, millennia ago. Protected by Anubis, Osiris enjoyed a position of unique power among the others, not quite being the face of the enemy, yet still in control of almost every situation.
The downfall of Osiris came when he overplayed his hand, attempting to use Daniel Jackson's subconscious memories of ascension to help him translate a tablet that would lead Anubis to the Lost City of the Ancients. SG-1 caught on and captured him, with the Tok'ra finally extracting the symbiont and freeing Sarah from its grasp. Despite the veritable wealth of knowledge, she would surely have retained, Sarah is never seen again after this, despite her prior relationship with Jackson.