I don't think that the Blood Rites (Raith/HWWB) magic fits in. The rest of it all ties together though.
The two common themes are the Red Court and people using magic that they have been given by someone else.
I don't know if the source of the black magic was giving it out to multiple parties (Bianca, LeBlanc, Sells, Denton, Kravos, etc.) or if they were giving it all to the Red Court and allowing the Red Court to spread the power to proxies of their own.
You could make a pretty good argument that the mysterious magic in the first few novels is the result of Bianca/Red Court using proxies to remove enemies (Sells targeted Marcone originally, Denton targeted Marcone and then was pointed at Harry, LeBlanc was targeting the White Court, Kravos was aimed right at Harry).