Monsterstuck

Basically, the sburb kids are divided between demons and hunters.

The Striders and Lalonde's are hunters

Jane, John, Jake, and Jade are all demons.

Jane and Jake are Second cousins and are the third Cousins of Jade and John (who are siblings).

Roxy and Rose are sisters and are half siblings to Dirk and Dave.

The trolls might join in at some point but I'm still not sure...

Long story short this isn't just a demon AU, not everyone is a demon and the Striders and Lalonde's don't only hunt demons, it's kind of like Supernatural, the kids fight monsters from time to time but the overall story is about demons and High school.