The feudal system of Mishima is built upon the ambition and martial skill of its Samurai. These fierce warriors will work for a lord within a standing army, or as a leader and manager in the clans business dealings; more often both.
However, a curious new form of warrior has taken to the field in more recent times- lightly armoured and equipped with the distinctive Yari-Juu; a Shogun Assault Rifle with a spear for a bayonet. These are commoners who have been armed by their Lords and sent into battle to support the efforts of the Samurai. They are known as Ashigaru, or light-feet, a reference as much to their role as to their lack of equipment.
The majority of the Ashigaru in the Solar System are employed by Keiretsu aligned to either Lord Heir Maru across Venus many warzones, or Lord Heiress Mariko in her ongoing battle with Capitol in the Freedom Lands and sand rivers of southern Mars. Lord Heir Moya, on the other hand, has a lack of fixed enemies and an abundance of Samurai, and is not known to employ the commoners in battle very often.
Just like the Samurai armies that the Keiretsu keep, the Ashigaru are employed in wildly different fashions. The Ryu-do Clan value training, and teach their Ashigaru to fight with everything except the forbidden secrets of Ki. The Gediggo clan, on the other hand, view service in their Ashigaru hosts as a means of atonement for mistakes for both commoners and Samurai. This means their forces are fanatical but woefully under-equipped. Ashigaru come from all parts of commoner society- male, female, young, old, tall, short even petty criminals are not turned away when they express a sincere desire to serve. The only people unable to join the Ashigaru are members of the Triads and technicians with skills too valuable to risk.