Lisa's sister is a Visitor Queen.
BiographyEditLisa sister was preserved when Anna had her last and final clutch. She kept her, should Lisa ever turn rogue. Still in her egg stage, Anna wanted Joshua to accelerate the age of the Queen, but Joshua had to perform tests on Amy to see if it could work. It proved successful and the Queen egg was age accelerated.
In "Mother's Day", Anna now knowing Lisa is a traitor, hatches the Queen egg so the Breeding Plan can be nearing it's completion. Anna then orders Joshua to put skin on Lisa's sister and to model it so it would look exactly like Lisa's. It proved successful, and seeing her new daughter looking like Lisa and not seen to be infected by human emotion, Anna believes she's perfect.Also in the episode, Lisa's memories were transfered to Lisa's Sister. It would explain why she can speak English in the time of a few hours. And Joshua confirmed that Lisa's memories were watched by her sister. Lisa sister then mated with Tyler, showing similar signs of sexual dominance unlike her sister but allowed Tyler to touch her. She also seemed to enjoy taunting him as she kissed him a lot before forcing his head the other way and looked at the camera, knowing the real Lisa was watching perhaps to taunt her that she was about to slaughter Tyler. After mating with Tyler Lisa's sister unhinged her jaw and slaughtered Tyler whilst Lisa was watching in despair, before preparing to devour his corpse.
It is not known what happens after, but Lisa's Sister would be trained to become the future queen, and would birth her offspring.