The society in the Imperium is broken up into several broad categories that are recognized in a similar manner in every province.
At the bottom is the slave. While slaves are not as common as they once were, many still serve the great noble houses.
Little better than the slave is the commoner, which includes tradesmen of various sorts like blacksmiths and cobblers and so on. These are the people who occupy anything other than towns or cities; those from villages and the countryside are bound to the land and its lord. They are not allowed to leave the work they were born into, so a farmer will always be a farmer; seeking fortune in towns and cities is technically illegal without express permission (and a lot of coin), but a name change can work wonders. They are not allowed to serve in any military-like force and are banned from owning weapons. Even slings and staves are looked upon with suspicion.
Townsfolk make up a majority of the population in more urban settings. These are the craftsmen and service providers in larger settlements. They answer to no lord but must still pay homage (and taxes) to the count or duke who reigns there. As with the commoners, they are not allowed to raise arms of any fashion. Even smiths are carefully watched to ensure all arms and armor are given to the proper authorities.
Merchants are a relatively new class in Kalos, rising from growing trade within the Imperium and with the nations to the north. They are given much more freedom than their city-living fellows but are still viewed with distrust by the nobility.
The Imperial Legions are the best-treated “low born” class in Kalos’ society. Most men in the legion were born into it, as their fathers were legion before them. They are often raised from the age of 10 to be dedicated to war and the Imperator. Orphans are often sent to the legion if they are young enough and often become the most dedicated Imperial servants. Men from other classes may join the legion as an auxiliary unit, often dedicated to manual labor and similar duties. These men may never become part of the legion proper, but their children may. While all legion are on continuous deployment, part of their pay goes to keeping their families in nearby settlements in special neighborhoods designed for legion families. This ensures that new recruits will never be in short supply. It is even possible for high ranking legion to attain nobility for valor and dedication.
On about the same level as the legion, the priesthoods from the various religious institutions hold a special place in society.