Form of Government
Witch Clans: have 13 representing them and then there are people below them, normal people basically.
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The Leader is like the top and will represent the clan during meetings.
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The Old Ones: a council that passes general laws and rules above each clans.
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it is relationship based, so the Leader's first borne will take over after the Leader steps down.  And it goes the same for the rest of the positions of the 13 unless they don't have a firstborne in that case they will choose another

Religion
The Ancient One: where the Witches get their powers from.  In the books, the Ancient One is the source of magic.  

Culture
Culture ish: the 13 are highly educated and know their magic very well.  First and Second- educated in magic.  Third- very good at fighting or defensive magic (but their Huntresses are the best)
Fourth- a mix

it is very hard to give birth to a healthy witch (wizards are not very common) so all the clans respect pregnancies.  Something like maternal leave, like if you're are Huntress, you HAVE to leave for a year for your health, goes along with the 13 and the normal people.  
BUT
If you give birth to a stillborn or a demon,  it isnt gonna be a pretty sight for you.  
Demon babies are like really bad because when they grow up, it is very hard to control them (especially their powers) and can kill a lot of people.  Called demons because they act like demons

Extra Facts
each clan has five Witch Assassins/ Huntresses.

The Four Clans
Two clans are magic based: so that means the witch assassins kill with magic.
I was thinking there would be one clan where they have magic, but are only defensive, so that means they are more fighters than spell casters.  The advantage is that their Huntresses are the best out of all the clans.
So the last clan are in between, have fighters and spell casters, in between.  

The Whatever First Clan
Elemental Magic, but not Earth or Fire but specific like Lightning etc.

The Erebus Clan
Black magic-closer to the Ancient One.  Curses, Jinx etc

The Whatever Third Clan
Are not spell casters, but are more defensive and have more healers than the rest of the clan.
The 13 are highly trained in fighting/defensive/healing.  
Good thing: Huntresses are the best out of the continent.

The Whatever Fourth Clan
The only clan to include Warlocks.
Imagine first and third combined.


This will be further developed later on....