The rules for natural healing say that a character who rests for 8 hours gains 1hp/level, and if they rest all day and night they gain 2hp/level.
So what about a monster who rests? Do they gain hp based on their CR, or their hit dice? For example, the party attacks a dark naga, but the fight goes badly on both sides. The party thinks it might be able to kill the naga, but risks losing one or two party members in the process. They retreat to lick their wounds. Two days later they come back to finish the job. Would the Dark Naga have regained 40 hit points (10 HD * 2 days) or 36 hit points (CR 8 * 2 days)?
it would be based upon a monsters Hit Dice.
Pretty much nothing dealing with a monster (except SR) is based on CR. Everything else is HD based.
Pretty much nothing dealing with a monster (except SR) is based on CR. Everything else is HD based.
I think there's more than just SR that is based on CR, but those are just rules/guidelines for monster creation. In actual play, CR is irrelevant to rules questions. It's always HD.
What I mean is this: SR might be based on CR, but that's for "character creation". In game, it doesn't matter that the devil in front of you has SR 20 because it's CR 10 and gets SR=CR+10. Its SR is just 20. If you advance it with the advanced template, the CR will go up, but SR will not automatically raise.
Oh, I know. I was just stating that, when in doubt, use HD not CR. The only thing I could think of (after attempting to memorize the Bestiary and homebrewing dozens of monsters) that dealt directly with the creature's CR was SR, if it had it.