The following is a list of cast members and characters from the Transformers film series.
Recurring cast and characters
Autobots
The Autobots are the main protagonists of the Transformers franchise who come from the planet Cybertron.
Optimus Prime
Optimus Prime (voiced by Peter Cullen) is the leader of the Autobots, the last descendant of the Dynasty of Primes and keeper of the Matrix of Leadership. Optimus Prime transforms into a 1994 red and blue Peterbilt 379 semi-trailer truck in the first three films, a rusty 1973 Marmon HDT-AC 86 semi cab-over truck in the beginning of the fourth film, and later a blue and red 2014 Western Star 5700 OP Phantom semi-truck.
In the first film, Optimus Prime arrives on Earth with Ratchet, Ironhide, and Jazz trying to find the AllSpark. At Mission City, he kills Bonecrusher and battles Megatron, but Sam pushes the AllSpark into Megatron's chest, killing him and destroying the cube; as a result, Cybertron can no longer be restored. Afterward, Optimus and the other Autobots form an alliance with the humans and work closely with them, with the resulting alliance being called NEST.
In Revenge of the Fallen, Optimus is killed by Megatron during a battle with him, Starscream, and Grindor. Near the end of the film, he is revived by Sam with the Matrix of Leadership and is fused with Jetfire, making him more powerful. Optimus Prime then faces the Fallen and Megatron. After a vicious fight, Optimus severely wounds Megatron and kills the Fallen, telling him to "give me your face."
In Dark of the Moon, Optimus revives Sentinel Prime using the Matrix of Leadership and reveals he was the leader of the Autobots before him. However, Sentinel betrays the Autobots and joins the Decepticons to restore Cybertron with the Pillars; meanwhile, the Autobots are sent into space. During the battle in Chicago, Optimus kills some Decepticons, including the Driller, Shockwave, and Megatron before he kills Sentinel Prime. In the film, Optimus is depicted with a trailer similar to his Generation 1 counterpart, and has been redesigned to look more heroic. The trailer contains enhanced weapons and flight gear. Optimus loses his right arm to Sentinel Prime at the film's climax.
In Age of Extinction, he is hunted by Harold Attinger, Cemetery Wind, and Lockdown, who is working for the Creators to bring him to Cybertron and kill any Autobots who refuse to give up his location. A badly wounded Optimus is discovered by struggling inventor Cade Yeager, who shelters him. Escaping the eyes of Cemetery Wind, Optimus leads the Autobots once again, taming the Dinobots and rides Grimlock to fight Galvatron and his new army of man-made Transformers. After defeating Galvatron's army, he kills Attinger and Lockdown. He sets the Dinobots free and asks his fellow Autobots to protect Cade and his family before taking the Seed into space and going after the Creators. At the start of the movie, Optimus uses a mode similar to his G1 counterpart but with a lot of rust.
In The Last Knight, Optimus arrives at Cybertron, now a dead planet. He finds Quintessa, the Prime of Life, who brainwashes Optimus to do her bidding of destroying the Earth, which she reveals is an ancient enemy planet, Unicron. She tells Prime that he must retrieve her staff to rebuild Cybertron. Prime's eyes turn purple and becomes Nemesis Prime under Quintessa's control. Just as he is about to kill Bumblebee, Bee speaks for the first time in ten years, which causes him to return to normal. He rides Dragonstorm into battle. After defeating Quintessa and saving both worlds, Optimus and the Autobots return to Cybertron, which has joined with the Earth into one planet.
Optimus Prime reappears and appears similar to his G1 counterpart in Bumblebee. He leads the Autobots against the Decepticons trying to take over Cybertron, but is forced to retreat when Decepticon reinforcements led by Soundwave and Shockwave attack them. Realizing that Cybertron has fallen, he orders all Autobots to get to their escape pods. He gives Bumblebee the task to protect the Earth and set up a base for them before being attacked by Ravage and other Decepticons.