(urth) Standard Wolfean Riddle

[Lee Berman]

The recent discussed inspired me to recheck the relevant text on the origin of
Hierogrammates.  I think this sequence is a good example of what David Stockhoff 
and I mean by Wolfe giving an answer with one hand and doubt in the other:
 
>Apheta- "They (Hierogrammates) are those of who you spoke, those who were
>made in your image by a race cognate to your own" 
 
>Apheta- "we must go masked...with the appearance of your own race, the race
>that our parents, the Hierogrammates,  first set forth to follow" 
 
>Tzadkiel- "I am as I am, your own race having made us so before the apocatastasis,
>Were you not told they had shaped us in their image?"
 
>Severian- "The Hierarchs and their Hierodules-- and the Hierogrammates..they bring us
>through the pain we brought them through and..."
 
>Apheta- "....you in turn will make us go through what you did....Your race and ours are,
>perhaps, no more than each other's reproductive mechanisms."
 
>Apheta- "Tzadkiel..had examined the future and found the chance high that you would
>bring a fresh sun to your Urth and thus save the strand of your race so that it might
>produce ours in your Briatic universe.
 
>Apheta- "it may be that from your ancient Urth, reborn, that the Hieros will come. I
>believe it to be so."
 
 
So, did Urth's race of humans create the Hierogrammates or some other, cognate race? Is it 
possible to say? Is one more answer more likely than another?