I was thinking that maybe Rena is outside in the woods surroubding the castle setting up the defensive barrier around the property. So he could propably be back any time to join for whatever you have planned.

And about his position. He has been with the coven for a year or so. Maybe the one who took him in perished in an unfortunate accident? There is also the issue on how he addresses the head witch. He kneels? Calls her mistress? And how is he treated?
[@Any GM/Co-GM who cares to read]