You’d never know it by looking at her, but that woman is an alien’s worst nightmare.
Dr. Vahlen is the lead scientist, seemingly an astrobiologist by profession, attached to XCOM who oversees the project’s research laboratories. In XCOM 2, her role has been taken over by researcher Richard Tygen. She is stated to be ‘missing’.
XCOM Database
Dr. Vahlen is the Chief Scientist assigned to the XCOM project. She leads the Research Team’s efforts with great enthusiasm, as her particular interests lie in finding ways to adapt the alien technology to advance human scientific developments.
Dr. Vahlen provides medical information and linguistic assistance to Delta Squad during the tutorial mission.
Following the tutorial, she introduces the Commander to the research laboratories and on occasion advises the Commander with some helpful tips about alien specimens and how to capture them, and also asks that explosives not be used so that materials and weapon fragments are preserved rather than destroyed outright. While informative, it is generally advisable to ignore the last piece of advice at higher difficulties.
She also oversees all alien interrogations and autopsies. In the later stages of the game, she advises the Commander in the use of psionics and observes The Volunteer when he or she activates the Gollop Chamber.
In XCOM: Enemy Within, Dr. Vahlen helps unlock the secrets of Meld and advocates for using the substance to perfom genetic modifications to XCOM’s soldiers. This is the cosplay porn version.