Brian Lumley 
Spawn of the Winds 

Stolen from Earth by Ithaqua the Wind-Walker and transported to the alien world of Borea, a team of ERP-talented earthmen are faced with a terrible choice: join with the Thing That Walks on the Wind in his eternal war with Armandra and the People of the Plateau, and become his mindless slaces or side with Armandra and risk the perils of the Plateau – especially its Cavern of Madness!Such a choice might seem easy, for at least the People of the Plateau are human…but is Armandra herself human As Ithaqua’s daughter, who can say which way her loyalties will turn when the chips are down and Ithaqua walks on the wind?