Poll #20: City of Swords Campaign Setting
Well, you guys can roleplay being whatever you want. In the campaign everyone will have a different backstory. Serfs/slaves to a guild, official members/mercenaries, high ranking citizens, young nobles with nothing better to do than go thrill-seeking in the arena despite your family's warnings, whatever. You can even be a noble or citizen who was in the wrong place at the wrong time and was captured and nobody recognized who you were nor would they listen because you didn't have any identification on you at the time. Maybe you're an innocent person framed for a crime and turned into a gladiatorial slave as punishment? Who knows. Backstories are entirely up to you, as long as they fit.
The guilds themselves are merely organizations that gather freelancers together. You can have all types of freelancers of any profession, although the most common are "muscle for hire" and "magical craftsman". Guilds grant a character special rights, protections and boons. Instead of begging for scraps, you're guaranteed work when you need it and can take time off when you see fit and negotiate rates and have paperwork processed by people more experienced with bureaucracy than yourself. The guild enforces contracts so you don't have to worry about being betrayed or swindled and they take only a small % of your profit. Guild competition also helps the economy as prices and services are constantly competitive to win over a patron's business.
In a world constantly at war, warriors and magic are an ever-necessary resource and in a global economy (yes, that's right, a fantasy world with a global economy) they are used as both as soldiers and currency by rich factions. A "seasoned warrior" or "master magician" (high level character) are precious resources from a political perspective. Many even become political leaders themselves.
So think of "guild" as "company/union". You have some small guilds and some big guilds. The guilds you guys have created here are all small because our game is small (only 16 players using 24 characters).