Quote Originally Posted by griffin View Post
I guess Optimus Prime wasn't the last prime after all... If it is a pre-existing character, The Fallen should have known about it, or at least sensed it if he could sense the death of Optimus in TF2.
Wasn't it stated in the films that Megs & Optimus are brothers and that Optimus was descended from the original Primes? Wouldn't that make Megatron a Prime as well?

*EDIT*
found the quote about them being brothers

Optimus Prime: [to a dying Megatron] You left me no choice, brother.