Maj. Gen. James "Chaos" Mattis

Mattis is the Marine division commander driving the invasion of Iraq, a real general glimpsed mostly through his effect on the men below him. He turns up to deliver blunt, oddly stirring pep talks to exhausted troops, pushing his units forward with a mix of bravado and genuine care for casualties, then vanishes back up the chain of command.

The show resists turning him into caricature or hero worship, letting Robert John Burke play him as a genuine oddity: theatrical, quotable, unnervingly competent. He appears just enough to remind you that the absurdity and horror the grunts endure is being orchestrated, calmly and with conviction, by someone several ranks and a world of experience above them.