So, I'm going to be pitting some demons against my players, but I have a question first. With the demons, we'll take the Chasme, it has a Drone attack in which it "produces a horrid droning sound to which demons are immune." Now, for my question: If you have a Tiefling character in the party, and since they are technically half or part demon, would that mean that they are immune to such attacks as well, or would they roll their saving throws with advantage instead, or not even be affected because their heritage is so diluted?