Cave Johnson

"We painted subliminal messaging all over the walls in this next test, so if you feel the sudden urge to buy a bunch of Aperture Science merchandise afterwards, we'll count that as a success." - Cave Johnson

Cave Johnson is the posthumous overarching antagonist from both Portal Stories: Mel, and Portal 1 and 2. He briefly guides the player- and, by default, Mel, through Aperture via voice recordings at the beginning of the game. After Mel wakes up, Virgil briefly pretends to be him.

Trivia

 * He is voiced by J.K. Simmons in Portal 2, but is voiced by Harry101UK, aka Harry Callaghan, in Portal Stories: Mel. Callaghan also voices AEGIS and Rainbow Core.
 * In the beginning of the game, a recording of Cave includes a part where he fires an employee for misspelling ‘station’. This mistake was actually made by one of the developers, and they all found it so funny that they included it in the game as a joke.