Treating Cursed Lycanthropy as a sort-of "reverse Polymorph" wrt hp

[Segev]

This is inspired by the thread about a PC becoming a lycanthrope, but I think the topic might drift from helping with that poster's specific problem, so I'm starting a new thread.

When a PC (or, really, any character, but this is especially useful for dealing with PCs and player will/knowledge) contracts Lycanthropy, one of the problems that can arise, balance-wise, is that even if he's resisting the curse, he's now immune to nonmagical b/p/s damage, which can be overwhelmingly powerful at tier 1 and even tier 2. (Consider that that's better than high-level, expensive spells and really really rare armor properties.) Plus, if you want the tension over "has he been cursed?" you have an issue when you tell the player, "You take 0 damage from the attack." That's a dead giveaway, in and out of character.

However, in folklore, one of the ways the "invulnerability" of werewolves manifests is not as impenetrable skin, but as ultra-fast regeneration. So here's my proposal: as long as a character is resisting the curse (which includes when he's unaware of it), he records hp damage normally. If he's taken to 0 hp by nonmagical b/p/s damage, or the DM determines that a "significant" amount of the damage he'd taken was nonmagical b/p/s damage, then when the character goes to 0 hp, he transforms into his animal form at full hp and becomes an NPC under the DM's control. (Just use the MM stats for the lycanthrope in animal form for this; the curse has him going bestial so he doesn't have the humanoid cunning behind it that he might on the full moon.)

He transforms back when he takes a short rest, and has whatever hp his animal form had (or full hp if that's somehow higher than his own).

When a character gives in to the curse, willingly embracing it, he either becomes an NPC or you let him have it as if it were a pretty big magical item, but you have a strong discussion about the RP consequences and the way he'll play his new alignment.

I would venture to suggest that, if he fails to play the alignment, you can force Charisma saving throws or make him an NPC for a scene as the beast takes over and he gives in to whatever temptations he was resisting, though you want to be VERY careful about that, and consider just retiring the PC to being an NPC if it happens too often.

[JackPhoenix]

Or simply don't give the damage immunity in human form.

[Segev]

Or simply don't give the damage immunity in human form.

That's what this amounts to, essentially, since the "immunity" is hitting against phantom hp that are a countdown to losing control to the curse. But I like it better because it keeps the theme more in place. Werewolves in fiction typically show signs of the curse through certain benefits before the curse fully takes over. It helps build the horror, and also makes for stronger conflict.

[Greywander]

This reminds me of an idea I had for a plot/mechanic, possibly for use in a JRPG. Your character is a vessel for a dark god, and you can transform into a dark form that is basically invincible and very powerful. But doing so causes a meter to tick up, and when it's full, it's game over as the dark god is reborn and takes over your body. You could just not use it, but if you drop to 0 HP you would be forcibly transformed (the dark god won't let you die, as he would die, too), and the game would be hard enough that not using the dark form is still possible, but extremely difficult. I feel like there was a Breath of Fire game that had a mechanic like this, actually, except it was a dragon instead of a dark god.

I think this sounds like a good idea. Basically, resisting the curse suppresses its effects, but if you drop to 0 HP then your resistance is temporarily broken, causing you to transform and become feral. I would probably build on this further. First, how do you transform back/regain control? Well, dropping the beast form to 0 HP should do it. You get knocked out, and you're back in your normal form when you wake up. But I feel like there should be an option to wait it out, too. Maybe the curse only exerts itself during the night, so dropping to 0 HP during the day doesn't cause you to transform, and if you do transform, then you'll change back at dawn. Otherwise, you might consider draining 1 HP at periodic intervals, causing the lycanthrope to eventually drop to 0 HP and fall asleep, turning back into their true form.

Next thing to consider might be progression. We could represent your resistance to the curse using a value. Let's say it starts at 100, and every time you transform, it drops by 10. After a long rest, you regain 3, but you can only restore up to 9 for each transformation, meaning you're permanently down by 1 even after three long rests. This way, it takes a minimum of 10 transformations over a short period in order to lose yourself to the curse, which is still pretty forgiving, and it takes a maximum of 90 transformations over a long period (the last transformation always takes off 10). This is probably forgiving enough that you could have someone afflicted by the curse for the entirety of a campaign. Now, this is just an example, you could also do something like have regular WIS or CON saves to resist giving in, with the DCs getting higher as your resistance breaks down.

Last is the conclusion. Obviously, one possibility is that they give in to the curse and become a feral lycanthrope, making them an NPC. But you might also consider an option for taming the beast and living in harmony with it. This shouldn't be something easy to do, so make the player work for it. If they succeed, then they get to retain some minor benefits with no downsides. I might stick with just the ability to shapechange into beast or hybrid forms (i.e. no damage immunity, no change to STR scores, etc.). You might consider adding a new bonus that isn't present on regular lycanthropes, for example, I remember reading something about a clan of werewolves in some folklore that hunt evil spirits and protect the innocent, so maybe they get a 1/long rest casting of Detect Evil and Good or something.