Megatron

Megatron is a big hunk of losery metal. Not only is he beaten in pretty much any battle he has fought with Optimus Prime, on the off-chance he does beat him, he will just come back to life again. Poor Megatron.

But its not all bad. He does get to command a legion of insane, angry, suicidal and utterly overpowered minions. Shame his second in command is always trying to stab him in the back.