The Pugwampi has DR 2/cold iron and DR 3/good. It uses whichever is better in any given situation.
If a creature has damage reduction from more than one source, the two forms of damage reduction do not stack. Instead, the creature gets the benefit of the best damage reduction in a given situation.
So if you attack it with a random club the DR/good applies and blocks 3 hp. If the club is holy then the DR 3/good is useless so the DR/cold iron applies and blocks 2 hp.
The regeneration rules do not address this case but I have to think it works the same way, so if you hit the NMT with fire then one of its regenerations stops working but the other doesn't. If you want to kill it you have to hit it with fire and hit it with good/silver (not necessarily in the same attack) in the same round. Hmm, then again, that's pretty darn powerful. I don't know how else to handle the case where it gets Regen 5 (fire) from one source and Regen 2 (silver) from another. Pretty sure it doesn't get to benefit from both regens every round, though.
Bloodline Arcana: Whenever you cast a spell of the summoning subschool, the creatures summoned gain DR/good equal to 1/2 your sorcerer level (minimum 1). This does not stack with any DR the creature might have.
The ability specifically stat it doesn't stack, so DR/ good AND cold iron is straight out.
The most punitive interpretation would be you don't get the DR/good at all.
However, I believe the correct interpreation is:
DR 3/good and DR 2/cold iron
If your weapon is neither good aligned or cold iron your damage is reduced by 3 (the higher of the two DR values).
If you have a good aligned weapon you will have damage reduced by 2 (from DR cold iron).
If you have a cold iron weapon you will have damage reduced by 3 (from DR good).
And if you have a cold iron good aligned weapon you bypass all DR.
As for the troll....technically we do have any rules for what happens if a creature has multiple sources of regeneration as far as I know.
The most literal way to run it is that the creature has regen 5 (fire) and regen 5 (good weapons, silver weapons, good spells). Which would effectively give it regen 10 each round, but that's probably not how it should be run.
I think the best way to run it is regen 5 that requires fire and either good weapon/spell or silver weapon to suppress. Then the template does something to make the regen better without making it overpowered.
The Pugwimpi has the best DR that applies to each individual attack. If it is hit by a good weapon it has DR2. DR2/cold iron still applies
If hit by a cold iron weapon it has DR 3. DR3/good still applies.
If it is hit by a good and cold iron weapon it has no DR.
If hit by anything else it has DR3. Both the DR/good and DR/cold iron apply, but only the higher value is used.
The troll has 2 sources of regeneration, but they do not stack.
Hit it with fire and the Nightmare regeneration still kicks in.
Hit it with good or silver and the regular troll regeneration still kicks in.
To stop the regeneration you have to hit it with fire and either good or silver. It does not have to be the same attack however, so one person hitting it with alchemist fire and another hitting it with a silver arrow would shut both regeneration types for a round.
Does that apply to the REGEN if the troll has ER/Fire and does not take damage from the fire?
I guess I'm asking if merely being exposed to fire shuts down the Regeneration for one round, or does the Troll have to actually be damaged by the fire (say a fireball that does 13 but the Troll has ER/Fire 15)?
Does that apply to the REGEN if the troll has ER/Fire and does not take damage from the fire?
I guess I'm asking if merely being exposed to fire shuts down the Regeneration for one round, or does the Troll have to actually be damaged by the fire (say a fireball that does 13 but the Troll has ER/Fire 15)?
It has to take damage.
Regeneration (Ex) A creature with this ability is difficult to kill. Creatures with regeneration heal damage at a fixed rate, as with fast healing, but they cannot die as long as their regeneration is still functioning (although creatures with regeneration still fall unconscious when their hit points are below 0). Certain attack forms, typically fire and acid, cause a creature's regeneration to stop functioning on the round following the attack. During this round, the creature does not heal any damage and can die normally. The creature's descriptive text describes the types of that cause the regeneration to cease functioning.
Beware the troll with a ring of greater fire resistance on one hand and a ring of greater acid resistance on the other.
Does that apply to the REGEN if the troll has ER/Fire and does not take damage from the fire?
I guess I'm asking if merely being exposed to fire shuts down the Regeneration for one round, or does the Troll have to actually be damaged by the fire (say a fireball that does 13 but the Troll has ER/Fire 15)?
If all damage from an attack is prevented, so are secondary effects (unless otherwise specified).
If all damage from an attack is prevented, so are secondary effects (unless otherwise specified).Does that apply to the REGEN if the troll has ER/Fire and does not take damage from the fire?
I guess I'm asking if merely being exposed to fire shuts down the Regeneration for one round, or does the Troll have to actually be damaged by the fire (say a fireball that does 13 but the Troll has ER/Fire 15)?
The Glossary states that explicitly for damage reduction. Do you have a source for generalizing it beyond that? It certainly ought to be true, but I don't think I've ever seen it.
Whenever damage reduction completely negates the damage from an attack, it also negates most special effects that accompany the attack, such as injury poison, a monk's stunning, and injury-based disease. Damage reduction does not negate touch attacks, energy damage dealt along with an attack, or energy drains. Nor does it affect poisons or diseases delivered by inhalation, ingestion, or contact.
Attacks that deal no damage because of the target's damage reduction do not disrupt spells.
No secondary effects [usually], no spell disruption.
/cevah