The noble families descend from either Vasadori’s associates, or people that have been favored by past noblemen, and elevated to noble status. Nobles are considered superior based solely on the percieved notion that they were born that way. These families live either right around the perimeter of a vassal’s castle, or within the castle itself. While this living arrangement keeps the noble class safer than anyone else, it also severely limits their freedom. It’s exceedingly rare for a nobleman to leave the safety of the caste walls.
Nobles are most often classes that require a higher learning, such as arcane spellcasters. More militant classes, including arcane classes such as warmage, are forbidden. The only martial classes accepted for noble classes are knight, the lowest ranked nobles, and swordsage, because it’s elegant style of battle is appreciated among the noble class.