Optimus Prime (Transformers Cinematic Universe)

"Fate rarely calls upon us at a moment of our choosing"

- Optimus Prime

"Were we so different? They're a young species. They have much to learn. But I've seen goodness in them. Freedom is the right of all sentient beings. You all know there's only one way to end this war: we must destroy the Cube."

- Optimus after Ironhide asks him why they are defending the human race

"Before time began, there was the Cube. We know not where it comes from, only that it holds the power to create worlds and fill them with life. That is how our race was born. For a time, we lived in harmony. But like all great power, some wanted it for good, others for evil. And so began the war. A war that ravaged our planet until it was consumed by death, and the Cube was lost to the far reaches of space. We scattered across the galaxy, hoping to find it and rebuild our home. Searching every star, every world. And just when all hope seemed lost, message of a new discovery drew us to an unknown planet called... Earth. But we were already too late."

- Prime narrating

Optimus Prime is the main protagonist of the live-action Transformers film series, appearing in the first film, Revenge of the Fallen, Dark of the Moon, and Age of Extinction. Though this is general, he is the tetartagonist of the first two films, with Sam as the protagonist, Mikaela as the deuteragonist, and Bumblebee as the tritagonist. Originally a peaceful Cybertronian scientist and the very last Prime of the dynasty, Optimus and his team of researchers studying the mysterious Allspark were betrayed by their security unit, the Decepticons, and its now corrupted power hungry leader, Megatron. Naming his squad of scientists Autobots, he used his team to fight the tyrannical Decepticons in order to stop them from getting the Allspark's awesome power. He is based off his original incarnation with the same name.

Transformers: Dark of the Moon
Optimus Prime serves as the main protagonist of the film, at the end of the film, he ends up killing Megatron by cutting his head off and killing Sentinel Prime by blowing his head to pieces.

Trivia
Optimus in this version has tendency to strike his foe's face.