Half-Life Wiki
Half-Life Wiki
This subject is from the Portal 2 era.
Coop logo
This article is within the scope of the Portal Project, a collaborative effort to improve articles related to Portal and Portal 2. See the project page for more details about the article status.

"Cave here. Man oh man. Wow. Greg's multiple universe theory was dicey, but you're pulling through with flying colors. We're all very proud of Greg. [pause] Oh, and you."
―Cave Johnson[src]

Greg was a character first cut from Portal 2. He first vocally appears in the Perpetual Testing Initiative DLC released for Portal 2.



Perpetual Testing Initiative[]

During the Perpetual Testing Initiative, Greg is acknowledged but heard only as mumbles in the background. Cave Johnson is frequently heard talking to him. Different variations of Gregs are known to exist in the multiverse, including a "Sally Sue Greg" in a universe where "Cavina Johnson" claims to be a woman (with dubious degrees of legitimacy).

Greg from the "prime" universe (the main universe of the Perpetual Testing Initiative) has a daughter who Cave finds "creepy", who at one-point sneaks into his office and uses the microphone to talk to the test subject, only for Cave to shoo her away and chastise Greg for letting her in.

Behind the scenes[]

When the developers realized that they would need a character to play off Cave Johnson during his recordings, they created a scientist character named Greg. However, they found it a waste of money to hire a new voice actor for a few lines, and instead economized by cutting Greg and adding Caroline instead. This allowed them to use Ellen McLain as a voice actor and provided an origin story for GLaDOS.[1] According to Cave Johnson, in a line which was also cut from the game, Greg fought a bear once.


  • Greg was first physically seen in Portal: The Uncooperative Cake Acquisition Game as an edited photo of Arne Magnusson


List of appearances[]


  1. Portal 2 commentary