In The Heart of the World
Fighters come from many walks of life, as they do in any campaign setting. Skill at arms comes in a variety of forms, and can be learned in any number of ways.
Some fighters learned their skills the hard way, growing up in dangerous regions of the Empire where learning to fight meant the difference between life and death. They might be street toughs from an urban slum, or farmboys from border towns where bandit raids and animal attacks are a common threat.
Others learned when they joined (or were conscripted) into the military. Such fighters tend to favour group tactics and strength in numbers.
Some noble families (especially those of Teiko-Tochi emphasize the warrior’s path as part of the duty of the aristocracy. Such fighters are trained in personal combat and tactics by grizzled and renowned veterans. Noble fighters are taught that personal honour is to be prized above all else, and such fighters are often haughty, arrogant, and quick to quarrel. Hot-tempered though they sometimes are, noble fighters have the combat ability to back it up.
The many mysterious monasteries that dot the countryside of Xin are home to a variety of martial arts disciplines. Some of those schools emphasize armed combat, and many a fighter has emerged from those monasteries, armed with a variety of exotic and lethal techniques. Such fighters tend to be calm, introspective individuals who are utterly lethal when roused.
In place of the knight-errant, China has the idea of the roving swordsman, who might fall into any one of the preceding backgrounds. Such swordsmen wander the land, fighting bandits and monsters, and protecting the innocent and downtrodden. This genre is known as wuxia, and it was pretty much the inspiration for this campaign.
Crouching Tiger, Hidden Dragon is just one example of a wuxia story (and a revisionist one at that) but there are many others.