Admiral Greyfield in Advance Wars. He tries to unite the nations beneath his boot after the apocalypse by killing everyone who says no. Anyone who disagrees even slightly he hangs. Anyone who shows signs of the recent deadly virus he executes. This leads to his entire army, which is several times the size of the protagonist's, getting decimated by said virus. The only reason anyone would follow him is out of fear of death, and he himself is a coward who has likely never even held a gun. His tactics suck both the times he's in play (albeit the first time he is being deliberately stupid just to make you look bad), and his CO ability is even worse.
Anyone else remotely competent given such an arsenal could have taken over the planet in no time at all. He is the Dr. Evil of military commanders.