The Book of the Beast (Secret Books of Paradys Series #2) by Tanith Lee

From the most ancient of days, the Beast has passed through the seed of generations, preying on the unlucky, the unwary and the unchaste, its appetite ravenous and eternal.
A haunted house and a ghostly woman are the instruments that release an ancient curse upon the forgotten city of Paradys. As a savage, unholy beast prowls the city’s streets, a young student seeks to uncover the secrets that will lead to his salvation. Lee infuses this dark tale, the second volume in the series, with a dreamlike quality that hovers, like the world in The Book of the Damned, on the border of reality.