This book left me with a lot of questions and ended with a confusing deus ex machina that isn’t fully explained.

Fated mates are rare in this world, but the FMC is special, so she’s the mate of all 4 of the MMCs. It’s never explained why FMC is special, just that she definitely is. There are apparently two types of vampires, good-ish ones and psycho ones, and it’s not explained why that is either, except that it’s apparently in their blood?