But I'm pretty confident that my negative-levels-are-aging system isn't actually balanced against real negative levels, and inherently couldn't possibly be. And, though it makes the game easier and simpler for people who don't already know how negative levels work, it does make it more complicated for people who do. So I'm considering going back to the original negative levels system.
But I love aging effects, and want to them to matter in the game as much as possible. I've already got the rule that every time you're resurrected, you gain some age, but resurrection doesn't happen all that often.
There are only two monsters I know of (from sourcebooks I allow) that have age-increasing powers:
- The phane, an epic-level (CR25) monster which has the ability, after putting characters into temporal stasis, to age them at a rate of 1d4 years/round, no save. It specifies that targets take the physical, but not mental, effects of aging.
- The ciruja plant (CR3) from Dragon Compendium. After a fairly complex and reasonably easy-to-avoid process of paralyzing the victim then burrowing into their flesh, it starts draining youth at a rate of 1d10 years/round, no save. It, too, specifies that "this has no positive benefits for the victim", specifically calling out things that "might grow more powerful with age" (e.g., True Dragons).
But this brings up a good point: I really should have rules for adjudicating harmful aging effects in general. Obviously, you shouldn't ever gain any benefit from being prematurely aged.
I'm going to immediately discard the possibility of "you advance an age category without gaining the benefits, but you could gain the benefits next time you advance an age category".
Instead, I propose this solution: characters, once they've been subject to such an effect, track their physical age and their mental age separately.
If you advance an age category in physical age, you gain the physical penalties. If you advance an age category in mental age, you gain the mental benefits. You can't die of old mental age, but once you hit Venerable you stop benefiting. You can die of old physical age once you pass Venerable.
Harmful effects, like the phane, the ciruja, or being resurrected, only ever advance your physical age. Beneficial effects, like reincarnate or any potion-of-youth type effects we might choose to include (probably necessary if age is to be an important thing, though I could be really mean and make them apply to both physical and mental aging at once), also only ever reduce your physical age.
This has the side benefit of doing away with the "age to Venerable. get reincarnated. repeat." cycle of infinite mental score increases.
I suppose it also means True Dragon advancement is mental, but that's unlikely to ever matter in a session.
It's one extra number to keep track of somewhere on your sheet, but it's worth it.