A In a word, vampires. There are two branches of Night-Children, but both stem from Notte, as he was the first. More, and Notte’s oldest surviving offspring (not his first, however). She’s immensely powerful, and has earned the right to run her Night-Child family completely outside of Notte’s rules. The tension between them is epic, and you can get a taste of it in FOR DAWS TO PECK AT.
The best possible advice I can give is do not approach.