There are 6 principal guilds in the game, some of these are subdivided.
4 Specialisations with distinct skills.
7 Priesthoods with common skills.
A single guild.
8 different skillsets, spread across 19 orders.
New players start out as an adventurer, this is a "guild of convenience" to support certain game mechanics that require a player to have a "guild level" defined by the 15 "primary skills" assigned to a guild, however it is not a true guild in that it has no guild houses or advancement structure.