Even in the most adventurous of cities, the majority of the population is comprised of the general NPC classes. 90 percent of the average population just doesn’t have the capacity to be great heros or mighty villains. Many of these don’t even learn more than the basic farming or labor skills found as a commoner. Local militia or levy members may have managed a level of warrior or two, so even a commoner might be able to put up a fight, but they just aren’t going to quite match the prowess of more powerful classes such as Fighter.
This being said, harsh times and tough environments tend to weed out the weak. That man in the bar might just be a boasting militiaman, but he might also have proven his mettle facing down barbarian hordes and be more than your equal. As a character, it is impossible to know just where someone’s skills and talents lie until they choose to show them.
For the purposes of organization, the classes are grouped as being NPC or PC. The original base classes comprise the NPC section, while later base classes have been added along with the other classes to form the PC section. NPCs may have PC classes, a PC might even choose an NPC class. The lines are rarely as clear in life as they are on paper. Players who choose to take an NPC class as their first level will gain some special benefit. Follow the links for more information on the class, which archetypes are allowed and any setting-specific information relating to that class.
Characters are not required to take an archetype.