Status Updates From Planet of Twilight (Star Wars)

I have so many questions. How are people just dying without any explanation? Is it different from the plague that supposedly broke out? Is the Death Seed actually just leprosy? What’s the vampire got to do with anything?

Ok so I had no idea this book was the last one in a trilogy and apparently the whole trilogy got really bad reviews. I’m skipping to the third book anyway, and I’m going to give I a try b/c one of the reviews said there are vampires in this book. So oof here goes.