Nightsister use dark side magick. And if you're saying the sith race isnt canon then you're saying nothing in KOTOR is canon. Connections to KOTOR have already been made canon because it is referenced in clone wars and rebels . Maul never called himself a sith lord that is just false. The only time I've ever heard maul called a sith lord is on that site which is questionable at best. And if you want to talk about things not being canon, force awakens and last jedi are little more than fan fiction as far as I'm concerned, those films are garbage and Lucas had nothing to do with them