i'm too tired to go in-depth on the stuff, but i will say: if you only play nid and njod, it is easy to get the impression that reala doesn't completely love wizeman either. and, if reala is as cruel, ruthless, and brutal as supplementary materials claim them to be, then why don't they do things so cruel, ruthless, and brutally? …the answer is probably the target esrb rating, but, still. (so, i guess it's not really "fanon", as it's canon, but… self-contradictory canon? telling-not-showing? informed characteristic? something along those lines)
and reala not being completely evil, completely loyal to wizeman, has much more interesting dynamics than just them being completely evil. because then you've got a reala who loves wizeman but is scared of him, a reala who cares about their sibling but can't show it for fear of punishment—and reala is additionally frustrated by how nights' departure causes reala to suffer more of wizeman's wrath… which also fits in with njod's themes of family quite well, as it's more like an abusive family relationship than a master-servant one.