Slight readjustment of place names and the cutting of a large infodump1 later, I read on:
Gladdis tut-tutted. "It just shows how out of touch you are, Edmund. You lie in that tomb of yours and don't come out from one century to the next. The orcish dead have always walked on Varoo, on three nights together at the dark of the...
The dark of the moon.
Which was shining just a day later in Chapter 7.2
1Infodump pasted into the notes in case the information is needed in Book 2.
2Well, to be totally accurate the text says, "It was fully dark. The moon had not yet risen," but that implies it will, which it won't if it's a new moon.