I did a little research and found that Caitron's book is happening concurrently to Blair's and each of the coven sisters books happen concurrently with another book in the series. I felt like the coven sisters were the characters that bind the group of books into a series but that is not how the writing duo known as Lydia Dare has them organized. I hate when that happens. Why can't everyone organize their book series in such a way as to make it easy on me. In just the way I would do it. Is that too much to ask? No!
I have read the 5 books in the Coven series, (Hear that Lydia Dare? Coven Series) and I liked them all. Had a small issue with Cait's book, but I forgive you.
If you like historical paranormal-vampire and Lycan (werewolf) then you should totally try them. I will list them in the order the author recommends.