A standard Infantry Squad numbers ten souls: a sergeant and nine Guardsmen. Every trooper carries the ubiquitous lasgun and a clutch of frag grenades, while the sergeant bears a laspistol and barks the orders that hold the whole formation together. Several such squads are grouped into platoons, and platoons into companies, until the arithmetic climbs into figures no single mind can truly grasp.
Though plain, the squad is endlessly adaptable. One trooper may trade his lasgun for a special weapon such as a flamer, meltagun, plasma gun or grenade launcher to answer a particular threat. Another may shoulder a vox-caster to summon artillery and coordinate the wider battle. Where heavier firepower is needed, a weapons team hauling a crew-served gun can be folded into the squad's ranks.
What makes the Infantry Squad formidable is not equipment but discipline. Drilled to stand firm and shoot straight, the Guardsmen level their lasguns on the sergeant's command and answer the foe with steady, interlocking volleys. Individually unremarkable and eminently expendable, in their serried millions they form the unbreakable wall of massed lasfire against which the enemies of Mankind are meant to be broken. They are the one resource the Imperium can always replace.