Theresa Chasar (Doom 3)

Theresa Chasar was one of the few female UAC employees in Doom 3. She is named after the sister of Tim Willits, the co-owner of id Software. She was also friends with Dr. Elizabeth McNeil. According to her PDA, she was involved in research with other UAC scientists on the Plasma gun.

During the Enpro level, the player can hear a female voice crying. Upon entering Theresa's office, she approaches him and pleads for help, but then a Lost Soul tears itself out of her head, ripping out her spinal cord, which then attacks the player. How exactly the Lost Soul got to be inside her in the first place is not known.

Many more Lost Souls are encountered during the game, although this is the only time when one is seen to originate from a living human.