Quote Originally Posted by Milo v3 View Post
The capstones of other classes never give something as powerful as automatic resurrections. There Immortality is generally no death from aging, this is eternal life except from aging.
I think you may be conflating things here a bit, because that seems precisely backwards or extremely hyperbolic.

Immortal removes their maximum age limit. It does not stop penalties from future aging, nor does it involve a type change (generally to Outsider) that makes them immune to bunches of spells. They just get to be really, really old. I'd argue that it's somewhat worse than the druid 15 ability, quite a bit worse that the monk 20 ability, and not inappropriate at 13 at all.

Undying allows them to come back from dead once per day. It's a very narrow form of contingency that arguably drops all of their buffs when it gets triggered (because dead things are objects, not creatures, and aren't valid targets). That comparison does make me reconsider its level though, and I might bump it to 15. But it's really not that strong and doesn't preclude them just dying a second time.

Quote Originally Posted by Yitzi View Post
Fluff-wise, I'd advise you switch it for the "doesn't get aging penalties" ability that monks and druids get. "Never dies of old age" has all sorts of fluff implications that you probably don't want (most notably that you're almost never going to change who the high priest of a religion is), whereas the "no aging penalties" approach actually has precedent (Deuteronomy 34:7)
Precedent is nice when it fits, but I'm pretty willing to ignore it when it doesn't ;-). In this case, I'm not very happy with the penalty removal part of the other class features. I don't have a reason to want to protect the physical attributes of the class in old age. And I am pretty happy with the fluff stuff and the high priest just changing really slowly. It means that, barring violence, every major religion has a high priest in the world at any given time without having to bring a new character up a bunch of levels every few decades. I imagine what would actually happen is that they would just retire to their deity's domain when new blood had risen to take over for them, and be summoned back if there was ever an opening for too long.