Shockwave

Coldly logical and lacking in personal ambition or ego, Shockwave was at first the least of Megatron's concerns. Shockwave's sheer destructive power was tempered only by his dispassionate approach. No blood lust, no battle rage...just the most effective and economic approach to any given scenario.

Unfortuantely for Megatron, Shockwave concluded that his leader's all-consuming passion for conquest was not the optimum solution...therefore, Megatron should be removed, and Shockwave himself should lead the Decepticons. No malice, no ego, just simple logic.

However, that was then, and this is now. Nowadays, Shockwave has learned to accept the horrid nature of the Decepticons and does his best to be loyal to his master.