Jade O'Neill is the daughter of Jonathan J. O'Neill from a nightmare alternate timeline, in which the Aschen secretly smuggled a deadly bio-toxin to Earth and used it to sterilize and decimate the human race. Due to this, combined with the domination of Anubis over the Goa'uld Empire and the ravaging hordes of Replicators, the human race was left on the verge of extinction.
Jade, an operative of the human resistance, in which her father served as Commander-In-Chief, embarked on a mission through time, together with her father, to 2004. After infiltrating the SGC and using a bomb that was designed to look real, but was a dud. Which was only to break up the treaty with The Pack to. avoid her future from happening. She was captured in her escape attempt from Cheyenne Mountain. She revealed to Daniel during her interrogation who she really was, since she pretended to be a major named Hannah and flirted with Daniel, even saying he reminds her of someone she had a crush on, which was the Daniel of her time unbeknownst to him. He was attracted to her and found her to be a engaging conversationalist. She teamed up with SG-1, successfully exposed and stopped the Aschen plot in time to save the Earth and kill the insane Aschen commander responsible for the toxin's development (ensuring the timeline was altered to a better outcome). Jade was injured on the Aschen ship, but recovered. She and her father spent a day at Jack's cabin, before heading back to their time. (SG1: "Relativity")