Rajiin

Xindi agent posing as a slave

A woman rescued from a slave market by Archer who is secretly gathering data on humans for the Xindi.

Rajiin is offered for sale by a slave trader named Zjod at a bazaar in the Delphic Expanse. In Rajiin, Archer rescues her and brings her aboard Enterprise, where she claims asylum. In reality she is an agent working for the Xindi, sent to gather biological information about humans for a planned bioweapon.
Using an unusual touch, she scans several crew members and leaves T'Pol in a coma after an attack. She is caught and held in the brig, but Xindi-Reptilians board Enterprise and take her, along with the data they wanted.