The Shepherd in Shadow - Song of the Scourgelands, #2

Mehren Tevaht wasn't supposed to survive his desperate gambit. Throwing himself into the abyss along with the truename of the demon prince should have been the end of it: as worthy an end as Mehren can picture for such a coward as himself, anyway. When Mehren awakens in a shadow-realm he's only seen in dreams with his beloved, the warrior princess Vierrelyne du Talorr, at his side, he knows the spell he meant to do went horribly awry.
Together, they traverse a realm both familiar and hostile while the sorcerer tries to figure out what went wrong-and how to fix it-if only to restore Vierrelyne home without him. Haunted by his own past history, and the dawning revelations of the doomsday cult which once held his undying loyalty, Mehren must choose a fate that will define the future for himself, for Vierrelyne, and for all the realms beyond......the realm of bodies, the realm of beasts, the realm of spirits, the realm of dream...the Scourgelands beyond the Known Lands of Derebor itself.