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Power sword, mini-rocket-firing pistol and a big cool hat. Et voila, you have just got yourself one of the most badass normal humans ever to exist in the whole grimdark nightmare that is Warhammer 40k.
Imperial Guardsmen are tough and loyal to the Imperium, but a good BLAM encouragement from a Commissar will ensure the troopers' morale always remains at one thousand percent. That pretty much sums up the job of an average Commissar: making sure that the men (and women) hold the line at all cost. These cool-hat zealots are also very quick to be on the triggers at the slightest notions of cowardice, Chaos taint or even donning your uniforms the wrong way; but their presence on the battlefield is nonetheless much appreciated due to their aforementioned role. After all, aren't they the ones that ensure us puny humans actually stand our ground against all kind of Eldritch abominations that the universe throws at us and even duke it out?