This is a job that only a small percentage of the population is has. There are many types of noble titles that come with a large range of different benefits and responsibilities. Most positions of power, such has high ranks in the military, government, or merchant organizations are usually held by nobles. Most Knight and above in the military are from a noble lineage.
Those with high ranking titles are hereditary, and automatically pass their status onto their children. Though it is possible to gain a noble title through hard work and skill, these titles are usually not hereditary. In Aouine these titles can also be received from becoming a pioneer and settling land at the edge of the wilderness.
Ideally, a noble is granted benefits of wealth and power because of the large responsibility and burden that comes with their position, however rampant corruption is common. In such a system, it is often difficult for there to be proper oversight and those of a lower rank or Commoners are ignored.