The raider class in Wandering Ronin has two functions: it allows new players a chance at a large number of lives to learn the skills needed to fight, and allows for someone who has no garb or sash on a particular day an optional class to play besides peasant. The raider is considered no better than a thug, and should be role-played as such.
From the Rulebook:[]
Raiders are the lowest form of combatants. They have little skill, no discipline, and no incentive to better themselves. They are sneered at and slaughtered like vermin wherever they are found.
Examples: Street gangs, flash mobs, drunken rioters, looters.