Guilds

Guilds are buildigns that are essential to conducting your spell research early in the game. Try to maintain more than 1000 guilds during this period.

Guilds provide the same population space as wilderness, namely 10. Guilds also generate magical items at random.

Skill acquisition

Guilds provide a bonus to skill acquisition time (tested across all servers). This is capped at 5%, so keeping 5% of your land as guilds can be beneficial once researching is completed.

(non)Related

The word guild is also used for groups of mages playing together in a coordinated way, e.g. Supporting Guild Status