Den of Thieves, David Chandler

Born and raised in the squalid depths of the Free City of Ness, Malden became a thief by necessity. But his skill at thieving has attracted more attention than he bargained for, and now he must pay a furtune to join the criminal operation of Cutbill, lord of the underworld – and one does not refuse the master and live to tell the tale. Stealing the coronet of the Burgrave would fulfil Malden’s obligations, though it is guarded by hungry demons that would tear the soul from any interloper. The desparate endeavour leads to an even more terrible destiny, as Malden, an outlaw knight, and an ensorcelled lady, must face the most terrifying evil in the land.