Holy cow, I found the epigraph for Dark and Deep. Better late than never.
So lived the clansmen in cheer and revel
a winsome life, till one began
to fashion evils, that fiend of hell.
Grendel this monster grim was called,
marsh-riever mighty, in moorland living,
in fen and fastness; fief of the giants
the hapless wight a while had kept
since the Creator his exile doomed.
On kin of Cain was the killing avenged
by sovereign God for slaughtered Abel.
Ill fared his feud, and far was he driven,
for the slaughter’s sake, from sight of men.