<Li> Thomas Lennon as the Chief of Staff . </Li> <P> Greg Anderson, Melanie Specht and Victoria Summer play Joshua's assistants . Han Geng portrays himself, playing the guitar and singing in a parked car that is magnetized by Lockdown's ship . Edward T. Welburn plays a KSI executive . Kevin Covais plays a motorist . </P> <Ul> <Li> Peter Cullen as Optimus Prime The leader of the Autobots who transforms into a rusty Marmon 97 semi truck and later, a blue and red Western Star 5700 XE semi-trailer truck with flame decals . </Li> <Li> Frank Welker as Galvatron A human - made KSI Transformer drone intended to be modeled after Optimus Prime, but ultimately using data downloaded from the remains of Megatron . It is later revealed that the Galvatron drone has become possessed by the Decepticon leader, who molecularly transforms into a black and grey 2014 Freightliner Argosy cab over trailer truck . </Li> <Li> John Goodman as Hound An Autobot commando unit who transforms into an Oshkosh Defense Medium Tactical Vehicle . </Li> <Li> Ken Watanabe as Drift A Samurai - motif Autobot, tactician and a former Decepticon assassin who transforms into a black and blue 2013 Bugatti Veyron 16.4 Grand Sport Vitesse and a Sikorsky S - 97 Raider Helicopter . </Li> <Li> Robert Foxworth as Ratchet The Autobot medical officer who transforms into a white and green 2004 Search and rescue Hummer H2 ambulance . </Li> <Li> John DiMaggio as Crosshairs An Autobot paratrooper and elite sniper who transforms into a black and green 2014 Chevrolet Corvette C7 Stingray . </Li> <Li> Mark Ryan as Lockdown An extremely powerful, relentless, heavily enhanced, ruthless Cybertronian bounty hunter who transforms into a grey 2013 Lamborghini Aventador LP 700--4 Coupe and is hired by the mysterious Creators to bring Optimus Prime back to them . </Li> <Li> Reno Wilson voices Brains A former Decepticon drone turned Autobot who has lost his right leg . </Li> </Ul> <Li> Peter Cullen as Optimus Prime The leader of the Autobots who transforms into a rusty Marmon 97 semi truck and later, a blue and red Western Star 5700 XE semi-trailer truck with flame decals . </Li>

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