Perhaps it are Vardemus and Clarke? I have a feeling Vardemus is another child of the Golem, impersonating the guy Caroline actually hired.
When Clarke got out; there was only one hooded person, and now he's out there are two? Too coincidental.
Plus, when he uses magic, there tends to be emphasis on his ring. Perhaps that ring is a source of magical power and Vardemus uses the magic of the ring in a similar way as the siphoners/heretics do.
The artifact Josie used, sucks black magic and maybe Vardemus stores that magic in the ring? Getting students to use black magic does mean Vardemus gets a continous power source, so obviously he would applaud it...
It's my theory to the figures.