There are six guilds, each granted an exclusive monopoly over one vital function of the city life by the state, in exchange for tithing to the Church (Sepulchre) and submitting to Inquisitorial oversight. None of them actually govern the city on paper, but they have considerable power.
Essentially, the guilds' monopoly is on the technology involved with a specific profession, as an indication of Sepulchre's trust in their ability to wield it safely and responsibly. There are doctors in the slums that are unaffiliated with Mythos, for example, but their clinics don't have the resources that Mythos does. In a similar vein, not every crafter is a Vulcani, but the Vulcani they have access to more resources (such as workshops). A crafter in the slums would have to make do with less, or find ways to get access to those same resources through other means.
Each guild claims one of the Saints as a patron. There is also a particle given to fully-vested guild members before their last name; for example, Joe Schmoe would be called Joe vae Schmoe once accepted as a full member of Mythos.
Note that the guilds typically work on an apprenticeship model; once a would-be member finishes their basic education at a Sepulchre creche, they would find a fully-fledged guild member to work from and learn for.
These fully-fledged guild members are called Sixers, while contracted labor without official membership, benefits or protection would be referred to as Yeoman.
A brief introduction to each guild is below; click on their links directly for more information.
Mythos
Bioengineering, gene-splicing, cyberware, healthcare. Their patron is Saint Vael, and their particle is 'vae'.
Symphony
Entertainment, fashion, news, gambling, vices, the Matrix, blood sports. Basically everything the city sees, hears and believes. Their patron is Saint Lyra, and their particle is 'lai'.
Pegasus
A mysterious guild whose members are unseen and unknown. Rumors range from Pegasus being a front for the Inquisition to it being a sinecure for the well-connected, but those are just rumors. Their patron is known to be Saint Cinder, but their particle (if they have one) is unknown.
Vulcani
Makers of arms, armor, weapons research, vehicles, heavy industry, etc. Saint Ferro is their patron, and their particle is 'kor'.
Sepulchre
The Church. The spiritual authority of the whole city. Their patron is Saint Marrow, the Prophet, and their particle is 'eir'.
Outriders
Salvaging, scavenging, and surface runs. Their patron is Saint Vesper, and their particle is 'ren'.
Last edited,