Today, Marvel Studios crushed Hall H with their 90-min panel which included footage from Black Panther, Thor and Infinity War. During the Thor: Ragnarok trailer (which you can view HERE) the very last scene shows The Incredible Hulk launching himself towards Surtur. This is the first time the charcater has been revealed for the series considering many assumed Hela was the films main antagonist.
Now during the Marvel red carpet after the event Comicbook.com got the scoop from the director himself Taika Waititi revealed Clancy Brown (voice of Lex Luthor is the Superman: The Animated Series) will lend his voice for Surtur:
“I did a little of the mo-cap stuff for Surtur, body wise, but then we have Clancy Brown doing the voice of Surtur,”
Thor: Ragnarok debuts this November