In an effort to explain my point, say you have two people in a tank that only fills up with water when a primal dies. One person breaths oxygen, and the other breaths water (yes I know water has oxygen in but this is an analogy). Each time the water fills up, Hydaelyn, or the person who can only breath oxygen has less air to breath until she drowns. Now let's say all life of Hydaelyn are akin to microbiota/normal flora to us, there's microbiota in the gut, on the skin, in the mouth, on the surface of our eyes and etc. In this analogy, there are quite a few germs that are called opportunistic pathogens, which are big deal when one's immune system is weak. It seems like WoD are these opportunistic pathogens, causing our poor Hydaelyn to go septic and die. The weird guy in the water is thriving because he has the means to sustain himself, and any "microbiota" that live on or in him.