Karla

Dossier: Test Instructor Karla "Betty" Bettmann, the complainer
 * Background: Former Aperture Labs test instructor. Fired and replaced by a robot attached to a lamp (probability of workmates hating her is high). Found her way with Mel from an alternate universe where Cave Johnson was pure evil, and a robot.
 * +Info: Obssesive compulsive behaviour, specially with flashlights, buttons and dangerous tools. Complains a lot.
 * Skills: Has an extensive knowledge in different top of the line robotics, computer hardware and software. Fair knowledge of hacking.
 * Reason for hire: "I did good work you know! I was good and they didn't appreciate it! Not one bit! They said I could keep my job if I got my brain scanned for some silly test! I wish I pushed those flashy buttons that said 'Deadly Neurotoxins'! " (Subjected to brain mapping for the Aperture Labs GLAaDOS Purple Morality Core AI "Betty" causing progressive lethal brain damage)
 * Appearance: Short hair, redhead. S.C.I. issued a purple H.E.V. Mk IV -with extra lights (by request).

Events
Karla worked at Aperture Science as a test instructor in Test Shaft 09. She complained all the time about how Cave Johnson was replacing people with robots and that he was going to kill everyone if he ever became a robot and went insane.

Cave ordered everyone that it was forbidden to complain, and made Karla the example by putting up propaganda on the walls featuring her as "Karla the complainer".

The universe was then visited ("invaded" according to Cave's standards) by Bendy (Mel) from Earth Prime and Karla ended up finding Mel stranded at her world (Earth-0) where Aperture was in financial trouble.

Karla the complainer finally had a test subject to instruct after a long time since the robots took over most of the Test Chamber 09's workforce. It was the first time in a long time someone could use her help so she was eager to assist Mel.

But this was not a happy sight to many scientists that were annoyed by her personality. So she was offered to take part in another project while Mel was taken away to be stored in a cryopod. So Karla, seeing that the scientists were friendly towards her again, she fell into the trap and agreed to help with project GLaDOS to develop the brain-mapping tool.

Her brain was one of the first attempts at brain-mapping. They used her copy to create a lame welcoming lamp robot called GLAaDOS, which replaced her as test instructor after she was then fired for being "not useful anymore" and "annoying".

Karla's brain was diagnosed with a deadly tumor. She was jobless, frustrated and without a long future. She went home, where she then unknowingly waited for Sven Co-op's recruitment plan invitation.