Oh my... That particular sentence does make the perfect storm.
If you were referencing Aya specifically, or the robed man specifically, I would definitely say 'whom.' Yet the sentence is referencing another character through the assumptions (perception) of Aya, therefore I would want to say 'who.'
The robed man and Aya would be the subjects/objects (nouns), whereas the assumption of Aya would be a... Pardon if I screw this up... A preposition?
Every ounce of my grey matter wants to scream out "whom."
Usually I try the 'Jeopardy' approach to a sentence for this. Although in Jeopardy they are supposed to say "What is.." if it's proper grammar referencing a personality it should be "Whom is..."
Who could it be, that malignant shadow staring off at me from the other side of the room?
Whom is Bob going to ask out on a date, Candice or Jordan?
This site might help if you haven't checked it out already. http://www.quickanddirtytips.com/education/grammar/who-versus-whom
I really want to go with "whom."
Hopefully, someone will come by -who- has more knowledge, than I.
-Whom- would that be, though, is a mystery to me.