I am Optimus Prime, leader of the Autobots from the planet Cybertron. We came to earth in the year 2007, searching for the Allspark which I sent into the stars. We gained a great many human allies, one of them being Samuel Witwicky.
Through the years we have protected earth from the Decepticons, hoping to bring peace to our adopted home. But instead we have lead it to it's partial destruction. I try to help the earth's leaders and governments to stop their war so they do not suffer the same fate as Cybertron. Cybertron -- my home planet -- of which some debris remains in orbit around Earth.
Despite my place being here, on earth, Cybertron calls to me. Perhaps one day, when the Earth can finally be at peace with itself and it's inhabitants, the Autobots and I will return. And perhaps we will be able to rebuild our world, and become one people with whatever Decepticons remain.
I am Optimus Prime, and this world, is our home.