Aye, this looks pretty neat! If y'all don't mind, I got an idea for the "witch power" thing.

There could be two types of witches: ones born with powers and those who had to make packs/deals.

Those born as a witch would be considered "Blood Witches" ( or whatever name sounds better). Their powers are passed down from generation to generation; making them related to those witches who first roamed the earth. Most Blood Witches either join or are forced into a particular Coven. It's easy on both the witches' and society's mind if these magical folks are working together. Covens have rules and expectations of their fellow members and are pretty strict. Some live in towns or mansions with their Coven while others are free to go about their lives. But this type of power is limited . Since they were passed down the family tree, they should be the same or similar to the original witch of the family. Lucky for them, their consequences are not too bad and they can channel their powers from within. Of course, they have to practice their magic but overall these witches are high class and. . . sort of respected in society? Well, before the Witch hunt that is. The "Good" Covens (a.k.a the rich ones) were forced to move to ghettos by the government while the "Bad" Covens (a.k.a the poor ones) were sent to jail. Still, there are some small covens who are still out there trying to mantain the lifestyle they had before all this. So if you want to be a witch in today's society, you better be born into it.

But those witches who make deals, oh boy.

Those who made packs are considered, "Devil Children" (or whatever sounds cool). Their powers had been given to them in return for their service or a trade (soul, kid, etc). In the eyes of both "Blood Witches" and society, they are the worse type of witches. Why would they go to great lengths to obtain this sort of power? Probably for selfish reasons or to cause mass destruction. Since Society is too good for these witches, they most likely would work alone; which is good. Its raw power and they don't need to practice to make this power stronger, but they do need to work on controlling it so it doesn't control them. Like any witch, their magic is restricted too.  With magic like this, their consequences would be more severe than the "Blood Witches", and whoever they made a pack with would have given them certain powers or restrictions; or not. They either have a personal goal or a task they have to complete, so their magic would help them complete it. Of course, not every witch like this is bad, but you can never be too careful. Any witch found to have made a pack would be sent to death. This is pretty sad since most people are accused of being a "Devil Child"; even the Blood Witches if they can't trace their roots back to a certain witch. More reasons to hate this type of witch. But these witches don't care about what "society" thinks or this "death penalty". They are more scared of the ""person"" they made a pack with and the consequences of breaking a deal are worse than whatever the government considers punishment.


This is just my thoughts; feel free to comment or criticize it.

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Onto what @BlackPanther posted, the spell book would be neat. How they get that book? Was it part of the family or did those rotten kids make a deal? Who knows. A consequence could be that particular witch is limited to the spells within the book, so if granny didn't write a lot, that witch is out of luck. 
The familiar? Neat too. But again, limited to what magic the familiar. I could see this being part of a deal, though. They keep the familiar alive and they got their magic. The familiar isn't really "dead", but are knocked out. Like Pokemon. Just give them some blood and they should be fine.