I'm brainstorming a plot for a possible large-scale Skyrim Mod which may or may not involve the death of said Daedric Prince. Not being an expert on all Elder Scrolls lore, I'm not sure what would happen to Werewolves, Werebears, etc, if Hircine were killed (and by killed, I mean killed in the Hunting Grounds, ergo definitely deceased). Is Lycanthropy a curse or an actual disease? I would assume if it were a curse, Hircine's death would cure all Lycanthropes on Nirn forever. If it's a disease, then maybe Lycanthropes would remain, but no longer bound to Hircine after death. Thoughts?
I'm trying not to play devil's advocate here, but this is a moot point. Hercine CAN'T be completely destroyed. Not even if killed in the Hunting Grounds. It doesn't work like that. This isn't D&D. Think of et'ada as more conceptual ideals rather than actual beings. At this point you can begin to understand what they are. The et'ada are the emotional manifestations of the Godhead within his Dream. Emotions cannot be destroyed or killed within the Dream. Even Lorkhan, the one that died, isn't gone. The plane(t)s aren't just of daedric creation. They ARE the daedra. Take ESO and Battlespire as a good example. In both games the Princes were defeated on their own planes. ESO especially helps provide evidence that this does very little to the Prince as he is immediately seen after you defeat him. All you do is release souls he had stolen. You wanna know what permanently destroying Hercine would do? It would destabalize all of Aurbis, as each Prince fills the space between the scopes in order to maintain the aurbical structure.
As for the other question:
Diseases are microscopic daedric constructs managed by Peryite. In the case of vampirism and lycanthropy, at some point they may have been something else, but they upset the balance of the Aurbis, and the Taskmaster won't have that. He provided downsides to the Prince's gifts to their followers. He balanced the gifts so that they would not overpower everything they encounter.
Pretty sure that for Hircine to actually DIE in a permanent way you would have to destroy both the Hunting Grounds, an entire realm, AND his avatar which will be trying to kill you. Which is no easy task, even for Daedra, and something a mere mortal is completely unable to do due to the sheer scale of his power. The Nerevarine, one of the most powerful mortals to ever exist, was able to destroy a pretty weakened avatar of Hircine in Morrowind, so it's logical it would take at least godlike levels of power to bring down a god.
Even if the mod somehow allows you to somehow convince a fellow Daedric Prince or Sithis (due to even the Aedra being too weak to actually defeat Hircine in his turf) to kill the Father of Manbeasts, what would probably happen is large scale destabilization of the entire universe, going beyond Mundus, and either create some sort of MASSIVE physical change to Mundus, or simply a grab of power between the Princes for the now free space in the universe
Or the most likely scenario, that Hircine's dissappearance would create disorder and destabilize the fragile balance in the world that can't really be fixed.
You can’t kill a Deadra, first off it’s impossible, second how are you even going to be able to kill him? It’s his turf and besides I’m pretty sure some fellow Deadra would help him if he really needs it, because if ONE Deadra permanently died, it would throw everything off balance and would probably wreck EVERYTHING. The gods aren’t dumb they know this and would most likely help Hircine if he needed it. Also, If Hircine did die permanently, people infected with Lycanthropy would still be around, even though Hircine is gone, the disease is still around, therefore it will always be around unless every last being infected with Lycanthropy was killed. It’s like any normal sickness, even if the original host dies, anyone infected still has it. Lycanthropy is not a curse because it can be cured without having Hircine himself do it. Some witches know a remedy to cure Lycanthropy. Hircine is my all time favorite Deadric god, I know all about him, if you have any more questions are thoughts on Hircine, I’d be more than happy to answer!