Alzen

From Memory Alpha, the free Star Trek reference.

Alzen was a Srivani scientist who boarded USS Voyager under cloak to conduct covert medical experiments on the crew in order to obtain data for the Srivani medical database. After being exposed by Seven of Nine, she was captured. Alzen explained that the Srivani were conducting the experiments to get data to cure diseases that affected their race. Alzen believed that there was nothing wrong with what she and her team of scientists were doing. She matter of factly explained that there would be a few deformities, and a few deaths, but that she would share her findings with Voyager. She also threatened to kill the crew if Captain Kathryn Janeway refused her offer. Janeway refused and foiled their plan when she sets Voyager on a direct course for the middle of the binary pulsar which could destroy the ship with the aliens aboard. The Srivani's two ships detached themselves from the ship and one was destroyed. Voyager survive and the Doctor removed all the devices from the crew. (VOY: "Scientific Method")

Alzen was portrayed by Rosemary Forsyth. This character's name was not mentioned in the episode, and is from the script.