- “You still fight for the weak. That is why YOU LOSE!”
- ―As Megatron
- “That is why I have no fear!”
- ―As Galvatron
Megatronis the main antagonist of the Transformers Cinematic Universe. He served as the main antagonist of Transformers, the secondary antagonist of both Transformers: Revenge of the Fallen and Transformers: Dark of the Moon, a supporting antagonist of Transformers: Age of Extinction within his prototype identity Galvatron, Again, one of the two main antagonists of Transformers: The Last Knight (alongside Quintessa).
Megatron was not always the viciously powerful and brutally direct leader of the Decepticons: he was once brothers-in-arms with Optimus and a student of Sentinel Prime, appointed to be Cybertron's Protector and commander of its Defense Force. But Megatron resented his comrade, knowing he was a Prime and therefore Sentinel's favored son. This anger allowed The Fallen to ensnare him and led to the revival of the Decepticons.
Megatron is a warlord, feared for his ruthlessness and brutality, traits that made even Optimus Prime wary of him. He was a complete megalomaniac, as when he wanted to control over Cybertron but ended up destroying it after a countless year war with the Autobots and Decepticons and then wanted the subjugation of the universe by attempting to seize power over the AllSpark. Megatron was somewhat of a social Darwinist, especially towards humans whom he considers insects and would have destroyed the entire Earth just to fulfill his goals. When he was resurrected for the second time in his life, and unleashed by KSI, he became extremely violent and uncontrollably aggressive, massacring every human who came close to him.
As a leader of the Decepticons, Megatron faced no problems while in command, his followers possessed the utmost loyalty towards him and his cause. In fact, the only Decepticon that Megatron did not trust was his second-in-command, Starscream, who had opted for his command, but Megatron is able to keep his loyalty in check using violence and intimidation. He also did not tolerate failure from Starscream and would brutally beat him and even just insult him if he was irritated by his second-in-command's sycophantic groveling. But despite this, Megatron himself answered to a higher power and was a willing servant to his master The Fallen, who he was very loyal towards on Cybertron; the renegade Prime was able to heal him when Megatron had been badly injured.
However, Megatron wasn't always a warmonger; back on Cybertron he co-ruled his native planet with his brother-in-arms and future rival Optimus Prime, but after hearing word of an ancient alien force coming to their planet to seize the Allspark and after this force was unearthed he was left severely injured, but was healed by the Fallen who was in the artefact and was able to manipulate Megatron with the promise of power and then began to desire the AllSpark which began him to create an army of Cybertonians called Decepticons.
Megatron is also narcissistic and arrogant. When he first fought Optimus Prime in the first film, and Optimus said it was just the two of them in this fight, Megatron retorted No, it's just me, Prime! Also, after being killed by Sam Witwicky, Starscream his first lieutenant took command of the Decepticons in his absence, he was enraged and came close to actually killing Starscream while claiming "even in death, there is no command but mine." also shows when Megatron savagely beat Sentinel Prime half to death as when he was goaded by Carly Spencer by being called Sentinel's "bitch" and claimed that Earth was his and wanted to be in charge of the Decepticons once more.
As revealed in Transformers: Age of Extinction, Megatron is also extremely intelligent and manipulative; after being decapitated by Optimus Prime, KSI used his head to hack Cybertronian encryptions but this ended up reactivating him and this allowed Megatron to trick KSI into building him a body called Galvatron and an entire army of Transformers so that he could seize the Seed and arise a larger one. But despite this high IQ Megatron can also be single-minded at times. In all of his faults, the only thing that Megatron loved was his home world Cybertron, so much so that he struck a deal with Sentinel Prime to revive it if only so he could be the one who ruled it.