Since the First Atlantis Reconnaissance Team changed the nanite base code from the Central data core on Asuras, some of them were able to take a different persona at will. That particular one chose to take the appearance of Jennifer Keller. She was part of what was left of Niam's faction and decided to leave Asuras, steal a Zero Point Module and built a copy of Atlantis, and manufacture nanite-based copies of Sheppard's team, to learn how to ascend, because her team wanted to find something called a "soul".
However, when the team found out about this, she confronted some of them and explained the situation. She put the team into holding, where she planned to wipe their memories and start again. However, the rest of the Asurans discovered what she and her group were up to. Since the group refused to rejoin the collective Oberoth chose to destroy them and sent one of his Aurora-class battleships to destroy the city. She informed the team of the situation and they were able to convince her to let them go so they could try to stop Oberoth and so the group's creation of them wouldn't be a failed experiment. Leading the duplicate team to the Control Room, the Replicator version of Keller gave them the core drive of a ship's tracking system and told them to take it to Atlantis as the core drive would allow Atlantis to track every Replicator Aurora-class battleship in the Pegasus Galaxy. Replicator Keller saw this as Atlantis' best chance of stopping Oberoth and urged the team to flee in a Puddle Jumper. Though Weir offered to let her come with them, the Replicator Keller refused, knowing that Oberoth could potentially track her and she would just be a liability to them. Shortly after the duplicate team escapes in a Puddle Jumper, the Replicator ship destroys the Atlantis copy, killing the Replicator version of Keller and all of the Replicators within. (SGA: "This Mortal Coil")
Behind the scenes
- While not given an official name in the episode which she appears in, the Asuran clone of Jennifer Keller is often referred to as Replicator Keller or Repli-Keller among fans much in the same vein as RepliCarter.