From Labyrinthe Wiki
Guilds are organisations that characters can join. They offer a place for mercenaries to meet like minded fellows and a source of benefits.
Guilds are either listed as Open or Closed guilds based on their membership critea. Open guilds may be joined by any character, although they may have requirements and restrictions on joining, battleboarding benefits, leaving etc. Open Guilds may gain Guild Benefits and Guild Items by doing Guild Specials.
Closed guilds are not open for all characters to join, and membership is limited to small groups. However closed guilds do not gain benefits in the same manner to Open Guilds although they may aquire Guild Items as normal.
Guilds are split into three categories; Professional, Political and Social. Each character may join as many guilds as he or she likes, however they only have one 'slot' of each type on their battleboard. This means that before the beginning of the day you must choose which guilds to battleboard although you must follow the restrictions of all guilds that your character is a member of!
Professional Guilds represent organisations that a character can join based on his or her class. For example a Warrior might join The Frontline and a Priest would join a Church. The Benefits gained from professional Guilds are aimed at making their members better at fulfilling their role and generally membership is limited to that class.
Political Guilds represent organisations that characters can join based on their political outlooks. Unlike the real world political parties these groups are more often organisations such as the Claws of the Circle who protect the interests of the Circle, or Fractured Thought, who's members seek further understanding of the nature of the Exostance.
It's relatively easy to create and maintain a guild at Labyrinthe, although the more powerful the guild becomes the more difficult it is to maintain it. The full rules on guild creation and upkeep can be found here.