Warmonger

Warmonger is, as far as most bots know, a Decepticon from the Marvel Comics UK portion of the Generation 1 continuity family.

An Autobot? Me? This must be one of your Decepticon jokes.

Warmonger is not really a Decepticon! He's actually an Autobot working undercover. And what a fortuitous choice for the job. Heck, his name is Warmonger, and he looks like a conehead. What can go wrong?

Fiction

Marvel Comics UK continuity

An infiltrator within Decepticon ranks had freed the captured Hot Rod, Kup, and Blurr. Megatron believed this traitor had to be either Warmonger, Octopunch, or Bludgeon, and so he ordered the three suspects to battle each other to the death. Warmonger handled himself well in combat, but at the critical moment refused to kill an incapacited Bludgeon. When Megatron saw this, he correctly concluded that Warmonger was an Autobot, and killed him.Aspects of Evil, Part 4

From Teletraan I: The Transformers Wiki, a Wikia wiki.