Theresa Chasar (Doom 3)

Theresa Chasar was one of the few female UAC employees in Doom 3. According to her PDA, she was involved in research with other UAC scientists on the Plasma gun. She was also friends with Dr. Elizabeth McNeil. Being one of the few women on Mars, she was forced to put up with a considerable amount of unwanted flirting from her male co-workers, particularly her boss Lloyd Renstrom. This had its advantages though, as her colleagues were always eager to assist her in her work.

During the Enpro level, the player can hear a female voice crying from Theresa's office. When the player enters her office, a cutscene takes over in which Theresa turns to the Player and pleads for help. Before the Doomguy can do anything, however, she convulses and her skull tears itself free from her body along with her spinal column, revealing the game's first Lost Soul before it attacks the player. 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.

Theresa's PDA can be found in her office. It contains the code for a locked cabinet with a Plasma Gun.

Trivia

 * Theresa is the only female character to be seen in Doom 3, though several others are mentioned on other characters' PDAs.
 * Many players mistakenly believe that Theresa's head tears itself from her body and transforms into a Lost Soul. However, if one views the cutscene in slow motion, they will see that the Lost Soul actually comes out of Theresa's head. Also, when gameplay resumes, if the player looks at her corpse closely, they will see that her head is still attached to her body. (Edit: It is Theresa's skull, it tears itself out of her head and leaves a bit of skin behind, but she is clearly seen to transform in the cut-scene.)
 * Theresa is named after the sister of Tim Willits, the co-owner of id Software.