Azemar the Bored is a vampire lord
The party encountered him in the Ocean Palace under the waves. Here there was an endless supply of fresh food, which when fed upon gave him a little contact high. There was a Palace and a ruined city. And a steady supply of treasure, which he could keep for himself. Occasionally he would recruit some of the inhabitants for his personal guard. It was a boring existence, and he planned to move on any day. He just couldn’t bring himself to leave.
Using his magical music box, he enslaved those who would enter the palace, further reducing their wills.