I've just got round to finishing Dark Heir and have been reading the discussions but I've not seen anyone mention this - did the Elder Steward (and by extension, Grace) know that Will is the Dark King?
The way she phrased things and the way she acted made me feel that she did, and that she told Grace because Grace has also been very shifty and mysterious so far. She also mentioned something about how the attack on the Hall wasn't their darkest hour (from Dark Rise):
“I thought in their darkest hour the king was supposed to appear. Isn’t that what Stewards believe?” said Violet bitterly. “That they’ll call for the King, and the King will answer?” Grace was looking back at her strangely,