Michael Gough

Michael Gough, Voice actor who protrays Deckard Cain

Michael Gough is the voice actor of Deckard Cain. He has also done the Cain rap humorous piece of music for Blizzard.

He's not a regular employee of Blizzard.

Trivia

Michael Gough the voice actor is sometimes confused with the English stage/screen actor of the same name. The 'other' Michael Gough is probably best known to Diablo's demographic as Alfred the Butler in the Batman movies of the 80's and 90's.
Gough's Website has dozens of samples of his voice work, but the only sample of Diablo is the Cain rap which doesn't' actually appear in-game.