According to Transformers mythology, only a prime can kill The Fallen which meant that this responsibility was on the shoulders of Optimus Prime. Thinking that he's responsible for its demise, he finds a way to bring the planet back to life. It allows for him to come back from the dead in a new body again, a new toy.
The action flick also sees the return of Josh Duhamel, Tyrese Gibson, Stanley Tucci, John Turturro and John Goodman. Will Optimus Prime betray the Earth. Did Optimus Prime kill Bumble Bee. The new mechanical warriors are still unnamed but their vehicle forms have been revealed. For example, the cartoon series, comic book and live-action movies are all different continuities but Optimus Prime has died in all of them. Optimus Prime is seen trying to kill Bumblebee at the end of the trailer. After his escape, Optimus decides that he would seek out the Creators instead of them hunting he and his fellow Autobots down. He certainly was going for a fatal blow, but whether or not he actually killed Bumblebee is uncertain until the actual movie comes out next year. Fair use is a use permitted by copyright statute that might. However, in order to do so he needs to find an artifact on Earth.