Optimus Prime is the main protagonist of the Transformers Cinematic Universe. He is the leader of the Autobots, the last Prime, and the brother of the Decepticon leader Megatron. He is also known as "Orion Pax".
When placed under the control of Quintessa, he is named Nemesis Prime.
He has appeared in all of Michael Bay's Transformers films as well as the reboot Bumblebee film, albeit he is completely redesigned in appearance. He was more of his G1 counterpart, his vehicle mode being a Freightliner fl86, equipped with his signature ion blaster. Though it may be the only weapon we see in the movie, he does have many more. Along with his ending scene in Bumblebee, Optimus Prime had his trailer like in Transformers: Dark of the Moon.
In the seventh film (Transformers: Rise Of The Beasts) Optimus says "I'm going to take back Scourge's key, and then...take off his head." That is the origin of Optimus Prime's "GIVE ME YOUR FACE" phase. This raises the question of whether Optimus is the one that was in the first five films, or if it is a different Optimus but with the same character.
He is voiced by Peter Cullen.