(urth) A Knight question

[transentient]

Hello, brand new rabid Wolfe fan here (just discovered him last year,  
I've read like 17 of his books  since). I've been browsing the  
archives here for a few months and I'd like to say thanks back  
through time to all for the enlightening posts over the years.

Here's a quick Knight question I don't think I've seen posted before:  
While Grengarm was dying, Able says that he opened his mouth and then  
something about "things which had been hidden were revealed to me."

I am assuming that Grengarm showed him a face inside of his mouth, as  
Setr opening his mouth and speaking to Able with Garceg's face. So  
who was Grengarm's inner face? Did I miss something that was actually  
stated, or was this maybe, something he had forgotten while in  
Aelfrice the first time, but would soon forget again anyways, once he  
was kissed by the Valkyrie?

Thanks!