Peter Cullen Optimus Prime (voice) Frank Welker Megatron (voice) Sumalee Montano Arcee (voice) Jeffrey Combs Ratchet (voice) Will Friedle Bumblebee (voice) James Horan Wheeljack (voice) Michael Ironside Ultra Magnus (voice) Peter Mensah Predaking (voice) John Noble Unicron (voice) Daran Norris Knock Out (voice) Nolan North Smokescreen (voice) Kevin Michael Richardson Bulkhead (voice) David Sobolov Shockwave (voice)