Protection, Resistance and Vulnerability

This is an order of application problem.

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Let's say you have a creature that has the following:

Vulnerability to fire
Fire resistance 20

It gets hit with 40 points of fire damage.

How much damage does it take?

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Now, we have a creature with:

Vulnerability to fire
Fire resistance 20
Protection from fire with 30 points remaining

It gets hit for 40 points of fire damage.

How much damage does it take? How much is removed from protection from fire?

Protection explicitly comes before resistance, so that part is easy.
Vulnerability is trickier. I'm not sure there's a written rule for that, though most gamers I know agree you actually have to take damage before vulnerability kicks in, so of the three it comes last.

Following this in your example:
Protection would eat the first 30 points of damage and is gone,
Resistance soaks up the last 10.
Vulnerability never comes into play.

Houserule I'm thinking of adopting:

Resistance/protection = half damage.

Thus someone with resistance/protection and vulnerability takes normal damage.

Protection explicitly comes before resistance, so that part is easy.

Vulnerability is trickier. I'm not sure there's a written rule for that, though most gamers I know agree you actually have to take damage before vulnerability kicks in, so of the three it comes last.

Following this in your example:
Protection would eat the first 30 points of damage and is gone,
Resistance soaks up the last 10.
Vulnerability never comes into play.

I'd point out that protection only explicitly comes before magical resistance... There's no rules on how it interacts with innate resistance that I can find. I'd agree, though, that it should be consistent and go protection -> resistance -> vulnerability.

Just realized my post was in error since vulnerability is x1.5 and not x2. My bad. Still, half is a lot easier to deal with than varying numbers.

Protection explicitly comes before resistance, so that part is easy.

Vulnerability is trickier. I'm not sure there's a written rule for that, though most gamers I know agree you actually have to take damage before vulnerability kicks in, so of the three it comes last.

Following this in your example:
Protection would eat the first 30 points of damage and is gone,
Resistance soaks up the last 10.
Vulnerability never comes into play.

So, Protection From Energy (the spell) explicitly *does not stack* with Resist Energy (the spell). Here's the spell description:

"Protection from energy overlaps (and does not stack with) resist energy. If a character is warded by protection from energy and resist energy, the protection spell absorbs damage until its power is exhausted."

So for the second example (Protection 30, Resistance 20, Vulnerability, 40 points taken) Protection from Energy would be used to reduce the damage by 30, Resistance would not come into play this round (though it would apply to subsequent attacks) and the subject would take 15 points of damage (10 + 1.5x vulnerability).

So, Protection From Energy (the spell) explicitly *does not stack* with Resist Energy (the spell). Here's the spell description:

"Protection from energy overlaps (and does not stack with) resist energy. If a character is warded by protection from energy and resist energy, the protection spell absorbs damage until its power is exhausted."

So for the second example (Protection 30, Resistance 20, Vulnerability, 40 points taken) Protection from Energy would be used to reduce the damage by 30, Resistance would not come into play this round (though it would apply to subsequent attacks) and the subject would take 15 points of damage (10 + 1.5x vulnerability).

This is wrong. The resistance kicks in as soon as the protection is depleted. The protection doesn't "turn off" the resistance, it simply supercedes it. So, for the second example the victim subject to 40 points will have the first 30 negated by the protection, and the last 10 then negated by the resistance. Victim takes no damage.

scm wrote:

So, Protection From Energy (the spell) explicitly *does not stack* with Resist Energy (the spell). Here's the spell description:

"Protection from energy overlaps (and does not stack with) resist energy. If a character is warded by protection from energy and resist energy, the protection spell absorbs damage until its power is exhausted."

So for the second example (Protection 30, Resistance 20, Vulnerability, 40 points taken) Protection from Energy would be used to reduce the damage by 30, Resistance would not come into play this round (though it would apply to subsequent attacks) and the subject would take 15 points of damage (10 + 1.5x vulnerability).

This is wrong. The resistance kicks in as soon as the protection is depleted. The protection doesn't "turn off" the resistance, it simply supercedes it. So, for the second example the victim subject to 40 points will have the first 30 negated by the protection, and the last 10 then negated by the resistance. Victim takes no damage.

I quoted the relevant text, it's fairly clear. Protection from Energy does *not* stack with Resist Energy meaning only one spell (the one of the highest level) applies in any given round. Resist Energy is suppressed until Protection from Energy wears out.

Here are the rules on stacking:

"Same Effect More than Once in Different Strengths

In cases when two or more identical spells are operating in the same area or on the same target, but at different strengths, only the one with the highest strength applies.

Same Effect with Differing Results

The same spell can sometimes produce varying effects if applied to the same recipient more than once. Usually the last spell in the series trumps the others. None of the previous spells are actually removed or dispelled, but their effects become irrelevant while the final spell in the series lasts."

So having the resist energy apply in the same round the protection from energy ends is the same thing as stacking. It's not explicit, but it seems clear that there needs to be a 1 round delay between the end of the protection effect and the start of the resist energy effect.