Cave Johnson is the posthumous overarching antagonist of the 2011 video game Portal 2. He is the founder and, for an unspecified amount of time, CEO of Aperture Science.
He was voiced by J.K. Simmons in the final project.
In the original scripts of Portal 2, Cave Johnson was intended to have a different role. He at first was envisioned to be the protagonist, but this idea was scrapped. He was described as "being trapped in a computer" while controlled by the player.
Later, he was intended to be the main antagonist of the story line. He would initially serve as a sidekick to the player, but would eventually betray them, and confront them for their "crimes against their brothers-in-arms". He would also go mad with power and lose touch with reality. The archetype of this character would later be given to Wheatley. This idea however was scrapped in favor of a sequel, which published Cave Johnson as a posthumous character who served as comic relief.
- During the Perpetual Testing Initiative DLC for Portal 2, which sees the protagonist Bendy travel across a multiverse, there is universe that depicts a similar scenario in which Cave was successful in uploading his mind into a computer (in this case, Glados) and eventually becomes corrupted with power. However, it is unknown if this was intended to be a nod to the original draft of the plot for Portal 2.