This could be a stretch, but the only thing that kind of goes against this theory is how big the Harbinger is. Her general design just seems to be a Prelate to me. She also has 3 fingers (much like San’Shyuum) and her general stature kind of infers it. Of course she seems to teleport but this could be a result of her suit and the tech she has in it.
Any other ideas on what she could be?
Edit: scrap is, Prelates dont have 4 fingers. It could be anything at this point