The Shattered World

Description for THE SHATTERED WORLD by Michael Reaves:

A millennium has passed since the Necromancer, in a bid for power, unleashed the cataclysm that tore the world apart. Saved from destruction by the combined efforts of opposing sorcerers, each fragment was given gravity by the placement of Runestones, then bound into orbit in an Abyss filled with air.

When Beorn of Osloviken, a master thief and shapeshifter, is captured following the theft of a talisman from the baronial palace of Oljaer, he becomes a pawn in a war between two factions of sorcerers. As The ancient spells that saved their world decay, both seek for the magic that will save them from apocalypse and reunite their world. Bribed by the enchantress Ardatha Demonhand with a promised cure of the werecurse that transforms and torments him, Beorn travels to Castle Darkhaven, carried on the back of the cacodemon Balandrus. There, he secures the Runestone of Ardatha's enemy, the sorcerer Pandrogas, only to be discovered and pursued into the catacombs, where he is swept from the fragment into the Abyss by a raging storm.

From The Abyss, where dragons fly and vampires prey on men, to the waterfront slums of Rhynne and the mushroom forest of the hell-world Xoth; from the gaping jaws and jagged fangs of chimera, hydra, and catoblepas to a nightmare battle with the Demorgorgon Sestihaculas and an ultimate battle for destiny at the Necromancer's tomb, Beorn flees, part man, part bear, on a quest for wholeness, his fate bound inextricably to a worldful of sorcerers in hot pursuit.