Greetings from Brazil!
I just stumbled into your games here and it really got me the attention, Specially What a King and Graduate in Necromancy, which I'll be looking further later.
So for this one... What does the guild members serve for? I know that if you have 3 units of a kind in a district you put one of the same there (which I assume are those 2 grey squares below the district), but, then what? I couldn't find in the rules what can I do with guilds.
Great work here, by the way!
Thank you a lot for both the interest and the question, I appreciate it! Following the rule you described, guild membrr is exactly that - just an extra unit that you can use in a challenge. If you have 3 same units in a district, guild is an extra space where you can put a fourth unit for free. So when a challenge occurs, you have an extra unit to deal with it:)