Rage of a Demon King — Raymond E. Feist

A loyal soldier and a wealthy merchant have served bravely in the flames of an enduring war that is ravaging their land. But swords, bows, wits and courage will no longer be enough to defeat the scourge that is descending upon their home. For a foul and terrible thing has escaped from a world already devoured to feed on one consumed by chaos--an insatiable nightmare creature of dark and murderous nature which seeks to own and corrupt the very source of life itself.

The final conflict is joined, pitting serpent against man and magician against demon. For those who battle in the cause of good, there will be victory... or there will be doom for all.

There can be no other outcome.