Reese is a sophisticated android created by nano-technology. Despite her incredibly advanced neurological systems, however, her mind remained innocent and childlike. Reese had created the first Replicators as toys, using the nanobots that were part of her system to reorder matter on a microscopic level and create individual blocks which she could control with her mind. However, she did not anticipate that when she taught her toys to replicate and protect her, they would kill everyone on her planet, and leave to spread across the galaxy.
When SG-1 visited Reese's homeworld, they found the ruins of an advanced civilization, long since destroyed. Left alone, Reese had put herself to sleep, but when she was brought to Earth and reactivated, she began to create new Replicators as toys. However, as they replicated in the thousands and Reese began to lose control, O'Neill was forced to destroy her to disable the Replicators and prevent their spread on Earth.
Although Reese could not be reactivated, she was given to the Asgard who were able to use her technology to broadcast a command through subspace that would call forth all the Replicators to a single planet, Hala, where they could be trapped within a time dilation bubble. However, the Replicators also recognized Reese's superior technology and were able to use her design to evolve into human form.
Portrayed by: Danielle Nicolet
Episode Reference: Menace