Not really; although Dhampirs can fit like a glove into evil campaigns seeing as they are spawns of the undead, the resource book has crafted Dhampirs into a somewhat neutral if not anti-hero type of race, seeing as how they hunt monsters as a personification of their undead heritage or consciously stay clear of those they may hurt, it shouldn't be difficult or out of place to have a Dhampir in a party of adventures.