Also, a thought about the whole Plague Rat and vampire bites bit. So blood magic can purge the infection, the vampire nature would be an instant cure…
Um… Could this be a reason La Commodora cured Tachyon? Because the “vampire world” episode established that she’d be really, REALLY nasty as a vampire. So did Maria Helena cure Tachyon because if she didn’t, Blood Countess was nearby, and we’d have something much, much worse?