The Night of the Swarm by Robert V S Redick (now out from Gollancz £16.99) is the final part of the Chathrand saga:
“The struggle to prevent the sorcerer Arunis from destroying the world reaches its conclusion.
At the centre of an infernal forest there is a clearing. Above it looms a seven hundred foot tall fragment of a vast tower. At its base, a group of friends. Exhausted, terrified. They stand around the body of a sorcerer, Arunis. In his wizened hand lies the Nilstone…”