Megatron (TransformersAemada.)

Megatron is a Decepticon from the Unicron Trilogy continuity family. When in his enhanced forms, he is known as Galvatron.

Megatron's fashion sense recognizes that stag beetles are the most evil of all insects on Earth.
Megatron is not content with conquering Cybertron. When he learns that a power greater than his own exists, he does not simply attempt to defeat it. He subjugates it, bends it to his will, dismembers its corpse, and integrates its power into himself. Megatron demands total submission from those around him. Any opposition is savagely crushed, any insubordination is violently punished. He is a monster in every sense of the word. Megatron tempers this barbarity with a regal, militaristic formality. He calls his closest troops “gentlemen.” He speaks politely and intelligently, with an air of sophistication. He makes it perfectly clear that he is fully aware of his folly.

Megatron's only weakness is his obsession with Optimus Prime. No matter how much power he gains, his last glorious battle must be against him. On the occasions when Prime seems to have been destroyed, Megatron has sunk into a deep depression. Once Optimus Prime is gone, there may be no more challenges in this universe.