Terin Ostler and the Axes of Evil

Book 3 of the Tales of Fortannis. One barbarian tribe has a prophecy saying the legendary hero Bishortu will unite the three warring tribes. Another has a prophecy that directly contradicts this, and they want Bishortu dead. And a third, which may or may not be comprised of werewolves, refuses to let anyone know what their prophecy says. Meanwhile, the Duke on whose land the barbarians live wants ...