Do you have 70+ relationship with Vampire? Else I think what you're missing is the dialog with the spirit at the bottom of the north dungeon, the dungeon where you find Vampire. When you go up north by using a ladder on the first map of the dungeon you can access a different area. Go down the stairs there to eventually find an area with a lot of nature and animals deep underground. The dialog with the woman there is necessary to advance Vampire's events.