The Vampires of Waterdeep campaign arc was a set of three linked adventures, written by Eric L. Boyd, which appeared in the pages of Dungeon magazine:
Blood of Malar (Dungeon #126)
Seductive vampires, hungry werewolves, sinister drug dealers, trouble in the sewers, and an undead beholder? Just another day in Waterdeep! The first adventure in the Vampires of Waterdeep Campaign Arc, “Blood of Malar” is a FORGOTTEN REALMS adventure for 13th-level characters.
Dungeon of the Crypt (Dungeon #127)
The High Hunt leaves the streets of Waterdeep and heads beneath the City of the Dead where monstrous criminal overlords compete for the favor of their mysterious master. It will take more than skill with a blade to cut through the web of deceit and treachery that surrounds the Vampire Master of Waterdeep. Do you have what it takes to survive the Dungeon of the Crypt? A FORGOTTEN REALMS adventure for 13th-level characters.
The Fireplace Level (Dungeon #128)
The High Hunt draws to a close deep beneath the noble villas of the North Ward, but bearding Waterdeep’s vampire master in his lair threatens to unleash the buried ghosts of a forgotten feud between two of Waterdeep’s merchant houses. The third adventure in the Vampires of Waterdeep Campaign Arc, “The Fireplace Level,” is A FORGOTTEN REALMS adventure for 14th-level characters.