"Those of you who volunteered to be injected with praying mantis DNA, I've got some goods news and some bad news. The bad news is we're postponing those tests indefinitely. The good news is we've got a much better test for you: Fighting an army of Mantis Men."Cave Johnson was first rumored as a Portal 2 character in a casting call discovered way back in 2008. Valve's Erik Wolpaw told us that the Portal 2 team actually didn't have Simmons in mind when writing for Johnson's character began. Originally, Valve envisioned Johnson with "sort of a southern voice," but eventually went with a more midwestern character.
Wolpaw wouldn't tell us how large a role Johnson has in the game, saying only that "you'll hear a lot of him."