Arthur knows the name Fionavar. It is almost a relief to him that he only knows it the once, in the set of memories associated with the summoning name Childslayer.

Arthur Pendragon, the Warrior, warleader of Britain, draws himself to his full height. Majesty surrounds him like a cloak; he lifts his head into the rising wind as if hearing a distant horn.

"This is the last battle, then?" Not a question. He knows.