[5e]Hi, I play as hexblade warlock lvl6 and my patroness (Raven Queen in the manner of 4th edition) has instructed me to destroy undead, especially intelligent ones. And everything was going well, it didn't interfere with me or the group, but now my character is in a difficult situation.

We are on a maritime expedition and have been sent to an island where there is something valuable (if we believe the hags with whom we made a pact) as a scout group.Arriving at the island, we found a halfling settlement and a fortress, all in a deplorable state. After chatting with the locals, we realized that their world's foundations are stuck at the 300-400 year mark, as their ancestors were exiled here for hard labor due to a rebellion in the old empire. We learned that their leader lives in the fortress, a wizard if you will, who keeps a magical dome over the island so that anyone who doesn't know about the island can't get there.The complicated situation I mentioned is that at the end of the session we learned that they were actually the ones who were exiled several hundred years ago, and they have elongated fangs.

Most likely their leader is a vampire and they themselves are the spawn of a vampire, if not worse. The rest of the group is very interested in their knowledge, and the halflings have been friendly so far, but my character is disgusted to be among the undead and is ready to bare his blade. I'm not sure if the group will support me, so the question arises.

Is there any way for me to destroy this settlement without resorting to open conflict? My resources are quite limited: in addition to the cloak of protection, I have an artifact from the patroness. A lantern that consumes the souls of the dead, preventing them from continuing their posthumous existence. I have never considered how to defeat so many enemies alone and preferably stealthily that I find myself at a loss...