Megatron (Marvel Comics)

Megatron was the main antagonist of the Transformers Marvel Comic strip.

Marvel Comics
Megatron was a gladiator from Tarn, who sought to turn Cybertron into a cosmic dreadnaught. To win his war for conquest, Megatron's Decepticons developed the art of transformation. When the wandering planet Cybertron was headed for an asteroid field, Megatron and a band of his warriors followed the Autobot ship sent to clear a path through the dangerous area, and attacked the weakened Autobot crew once they had achieved their goal. However, the Autobot leader Optimus Prime sent the ship crashing into a nearby planet, knocking them all offline.

After reawakening on Earth in 1984, Megatron was quickly ousted from command by Shockwave. Their power struggle continued for some time, with leadership changing hands multiple times, until Optimus Prime killed himself in a video game duel. Refusing to believe his nemesis was truly dead, the increasingly-erratic Megatron seemingly committed accidental suicide by blowing himself up on a space bridge in a fit of insane rage. However, the explosion had merely deposited him in the Dead End region of Cybertron, where he wandered as an empty, with no recollection of who he was.

After regaining his memories, Megatron captured Ratchet and forced him to restore the recently destroyed Starscream to functionality, this time as a Pretender, in a scheme to wrest control of the Decepticons back. But the ploy failed due to Ratchet's sabotage, and Megatron's attempt to escape the soon-to-explode lab via trans-time dimensional portalwas foiled when Ratchet tackled him. The two were thought destroyed, but they were actually grotesquely fused together in the explosion and left adrift in "unspace". Pulled from the void by Nightbeat, Fixit was able to separate their bodies, and kept them both in stasis aboard the Ark. They re-awoke when Galvatron, a future version of Megatron, attempted to hijack the ship, which had already been hijacked by Shockwave and Starscream. Megatron and Galvatron fought bitterly at first, but upon realizing who they both were, plotted to join forces... but then Ratchet crashed the ship into Earth once again, seemingly destroying everyone on board.

Generation 2
In one timeline, Megatron was rebuilt by the human terrorist organization Cobra, and he ultimately allied with Optimus against Jhiaxus, his Cybertronian Empire, and the Swarm.

Regeneration One
In one timeline, Megatron woke up in 1994, and proceeded to lay waste to the Earth, awaiting the day Optimus Prime would return.