Warmachine's most distinctive feature is the inclusion of Warcasters and Warjacks (the war machines from which the game derives its name). Warjacks, or 'jacks for short, are techno-steam powered constructs designed for waging war. They are, in general, powered by a coal-burning steam engine and guided by an arcane supercomputer-like 'brain' called a cortex. Heavily armored and often carrying oversized weaponry, 'jacks fill a role similar to traditional military armor such as tanks and artillery. They are several times more durable and powerful than normal troops, but are far more costly.