Get off your high horse and realize the game can say it however they want. Diablo is the name of the character in the game therefore you won't find it in any dictionary or google pronunciation thing. It is said how the game makers intend it to be said.
Wow internet tough guy, too bad you can find it in dictionaries and in google translate you type your words in. let me guess you go to school in Indiana too? Lol
The pesky game keeps trying to call it "dee-A-blow" (with an A like "at" or "hamper" but I know it is pronounced like "dye-blue" and the "a" is silent. --- "I am allowed double standards. You are not" -my ex