As far as I have understood, everyone is most welcome to write even about Cults or Covens rather than just kabals in the Kabal section.
And I just checked, if you look at the subforum description (when not inside the kabal-forum, but viewing it from the main forum-list) it says
"Share your Kabals, Covens and Cults with the rest of the community".
Which is a relief to me since I have three threads here for each!
I don't know much restrictions on the etiquette. Most write just text that describes the kabal/cult/coven and also mentions their leaders, but stories seem okay too as well as colour schemes. But there are specific forums for those too, so if you want to make a full project log or a thick novel for them you probably should make another thread to their own respective forums.
Adding a kabal as well as a coven in the same thread would probably upset the kabal if they don't have their own thread
but I am sure that it would be fine too.
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THE KABAL OF LOST HONOUR
THE CULT OF THE BURNING LEAF
THE COVEN OF THE HOLLOWED