Megatron was Optimus Prime's brother (he says so at the end of Transformers 1). So Megatron should be a descendant of the Primes. Why is he not treated like one in the movie?
If the decepticons were called the decepticons, then how the fuck didn't the autobots realize they were gonna turn evil?!
they both turned their back on their families.
Optimus says that because they are all brothers. They were all made from the same thing; the Allspark.
So no. Megatron isnt a Prime, just a brother
Let's face it, Transformers is not a franchise to be analyzed and dissected. You switch off your brain and enjoy it simply as eye candy.
In the comics and cartoon:
Optimus was originally Orion Pax, who was nearly killed by Megatron. Orion Pax was then later rebuilt by Alpha Trion as Optimus Prime.
Megatron was built in the secret Decepticon headquarters by the Constructicons.
Until Orion Pax was rebuilt Megatron was supposed to be the most powerful Transformer.
Megatron was using the word to gain sympathy, by bringing up the fact that they are both of the same race/species.
Just as monks consider themselves brothers.
Optimus didn't know he was descended from the Primes until some symbols on his head matched the symbols on one of the discovered sarcophagi of the Primes. Since then the Prime name stuck.
Megatron is not a Prime, like all his incarnations, he,s a powerful Cybertronian whose ambition and prowess allows him to incite war and form the Decepticons, just in the movie The Fallen is the one behind Megatron.
In G2 it's strongly hinted at that Megatron was created by one the First 13 Transformers (7 Primes in the movie) so it isn't outside the realm of possibility. It might come up in the third movie