Dragon Magic — B.V. Larson

In Dragon Magic, the fourth book of the Haven Series, the Kindred call upon Brand for help. Things are not right in their kingdom beneath Snowdon. Modi has led a treasure-hunting expedition deep into the Everdark, a place where spine-terrors, blind croaking things and great wurms reside. But it's been weeks, Modi is overdue, and the Gudrin fears the worst. Brand journeys into the magnesium bowels and beyond, and discovers things buried there that he wishes he had never disturbed.

Dragon Magic is a little longer than Shadow Magic.