How does resist all apply to an attack that deals two types of (non-combined) damage?

Resist all applies to all damage types (including untyped damage), reducing the damage by the resist amount. What happens when a single attack deals two different kinds of damage? Not combined damage, like "1d6 fire and cold damage", but two separate kinds of damage, such as "1d6 fire damage plus 1d6 cold damage"?

Consider the following example:

A creature with the following power...

Rimehound Bite
Melee 1
Attack: +X vs AC
Hit: 1d12+6 damage plus 1d6 cold damage

... attacks a player wearing Rimefire Plate, which grants "resist 1 all".

Does the Rimefire Plate reduce the damage by 1, or by 2?

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Rimefire Plate would only prevent 1 damage from Rimehound Bite.

This isn't actually about resistance. Each time you take damage, Rimefire Plate reduces the damage you take by 1. The real question, then, is whether Rimehound Bite deals damage once or twice.

From the RC, p222-223:

Damage Rolls

When most attacks deal damage, they do so through a damage roll: a roll of dice to determine damage. Whenever a power or other effect requires a damage roll, it specifies which dice to roll and how many of them. For instance, an attack might indicate that it deals 2d8+4 damage on a hit. When a creature hits with that attack, roll 2 eight-sided dice and add 4 to determine how much damage it deals.

Modifiers to Damage Rolls

Many powers, feats, and other game features grant bonuses or penalties to damage rolls. A bonus to a damage roll is added to the damage roll as a whole, not to each die within it. ... If a creature has a bonus to damage rolls and uses such a power, the creature applies the bonus to every damage roll of that power.

Extra Damage

Many powers and other effects grant the ability to deal extra damage. Extra damage is always in addition to other damage and is of the same type or types as that damage, unless otherwise noted. ...

Example: Valenae the cleric might have an ability that causes her to deal 5 extra radiant damage to undead creatures. That ability means she deals 5 extra radiant damage whenever she deals damage to an undead creature.

Rimehound Bite's untyped damage and cold damage are both part of the same damage roll. More specifically, the 1d6 cold damage is extra damage, a modifier to the main 1d12 damage roll, just like the +6 is; otherwise, it would also receive a +6. Because the damage is all a single damage roll, resistances and vulnerabilities are only applied to it once, so Rimefire Plate's resist all 1 only triggers once.

For example, if you roll a 6 on the d12 and a 3 on the d6, Rimehound Bite would deal 15 damage to a target with no resists, 14 damage to a target in Rimefire Plate, and 12 damage to a target with resist cold 30. The attack would deal 12 untyped damage and 3 cold damage, but because it's all part of the same damage roll resistances and vulnerabilities are only applied once, to the full 15 damage.

RAW vs RAI

For those who aren't rules lawyers, RAI is Rules As Intended, how (we think) the designers meant the rules to work, while RAW is Rules As Written, how the rules (as worded in the book / PDF / clandestine radio transmission) actually work. Generally speaking, it's better to stick with RAW rather than attempt to read the designer's minds to determine RAI, especially since RAW will usually accurately reflect RAI (assuming the designers are competent speakers of whatever language the book is in). Sometimes, unfortunately, the RAW is vague and could reasonably be interpreted in multiple ways (as is the case here), and on rare occasions the RAW is just plain silly, and clearly not RAI. In these cases, it becomes necessary for us to attempt feats of psionic prowess to determine what the RAI really is. Or we can, y'know, be logical about it.

So why should we suspect that the RAI is in fact for each damage roll to be treated as a single instance of damage, and have resistances (particularly resist all) applied to it only once, even if it contains multiple types of damage?

1. It's simple. It follows the 4e convention of having general rules that can be overridden by specific game elements as needed. It's a lot easier to have the rules say, "Resistances apply to each damage roll once," than it is to talk about how they separately apply to & interact with each different type of damage involved, and if there's a case where resistances really do need to apply separately to each damage type, that game element can explicitly say so.

2. It's less work. What if an attack deals 3 different kinds of typed damage? Which is easier, applying resist all once to the total, or figuring out how resist all combines with other resists for each type of damage involved?

3. It makes resist all less overpowered (and resist all is pretty darn strong already). Consider an optimized epic-tier ranger, a firesoul & stormsoul Genasi with the Extra Manifestation, Double Manifestation, and Shocking Flame feats, plus the Radiant One epic destiny. Each melee attack with CA deals a certain amount of untyped damage (the normal weapon damage from the power), plus some fire damage (from Shocking Flame), some lightning damage (again from Shocking Flame), and some fire and radiant damage (from Radiant One). Should resist all 5 reduce the damage from this attack by 5? Or by 20?

4. It's how most people interpret it already. Just ask the official WotC 4e Character Optimization sub-forum, where adding more damage & more damage types is practically the national pastime. Or better yet, ask the official WotC 4e Rules Q&A sub-forum.

Answer rescued from a previous question on this topic.

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Quick question for clarification: are you treating damage rolls with different damage type modifiers (1d6 fire damage + 1d6 radiant damage) the same as damage rolls with different damage types (1d6 radiant and fire damage)? – Ravn May 20 '14 at 16:51
@Ravn If they're a single damage roll they're treated the same by resist all. They're not treated the same by typed resists, but that case is covered fairly clearly by the rules. – Oblivious Sage May 20 '14 at 17:18

Rimefire Plate would reduce Rimehound Bite damage by 2, or 1 for each type.

RAW:

Resistance: Resistance means a creature takes less damage from a specific damage type.

Resistance, Against Combined Damage Types: A creature's resistance is ineffective against combined damage types unless the creature has resistance to each of the damage types, and then only the weakest of the resistances applies. Example: A creature has resist 10 lightning and resist 5 thunder, and an attack deals 15 lightning and thunder damage to it. The creature takes 10 lightning and thunder damage.

Resistance, Not Cumulative: Resistances against the same damage type are not cumulative. Only the highest resistance applies. Example: If a creature has resist 5 cold and then gains resist 10 cold, it now has resist 10 cold, not resist 15 cold.

Damage Type: Powers and other effects often deal specific types of damage. ... Most weapon attack powers deal damage that has no type. It is simply physical damage.

The keyword here is "damage type". Resistant does not stack against same damage type. However, combined damage type is different from multiple damage type, as written:

Fell Court Hellmage, Infernal Bolt (MV:TNV p.51) Hit: 1d8 + 3 fire and radiant damage.

verse:

Sunsearer, Sunstrike (The Plane Below, p.139) 1d6+3 fire damage plus 1d6+3 radiant damage.

The rule on combined damage type specify what happens to X fire and radiant damage, but does not specify what happens about X fire damage and/plus X radiant damage.

So what happens? We fall back to the general rule: Resistance means a creature takes less damage from a specific damage type. The rule on not cumulative resistances does not applies to damage roll, as written.

And we do have two damage types in case of sunsearer (in one damage roll).

If you have fire or cold resistance, you independently apply your resistant to each damage type. Your fire resistance does not help you resist cold damage, even when it is one same damage roll, and vice versa.

If you have fire and cold resistance, they are still applied independently. If you have fire and cold resistance from the same source, they are still two different resistances, and are still applied independently.

The new resistance rules does not change this mechanic. It just clarifies how you apply resistance to combined damage type, but only when you run into them. There exists no rules that make resist all apply differently from specific resistances.

RAI:

While applying resistance once for each damage roll seems to be a easy way out, it collapses when facing anything more than a simple resist all.

Let's say an attack deals 10 fire damage and 8 cold damage. If the target has both resist 6 fire and resist 5 cold, you have to decide what to do.

If you say the higher applies, what happens when the damage is 1 fire damage and 17 cold damage?

• Do you stand by resist 6 fire and say 5 point of fire resistance bleeds out into the cold damage?
• Do you say at most 1 fire resistance apply, so that cold resist 5 is now higher?

If you say the lowest applies, again what happens when the damage is 17 fire damage and 1 cold damage?

• Do you stand by resist 5 cold, confusing it with 18 fire and cold damage?
• Do you say at most 1 cold resistance apply? It is easier to give up and calculate them independently.

If you say both resistances applies, what happens when you have 10 fire damage + 8 cold damage + 2 fire and cold damage? You have to take high or take low for both resistances, which leads to same problems.

If you are still not convinced, many ghost like creatures has Resist insubstantial; Vulnerable 5 psychic. How are you going to apply insubstantial resistance when it is dealt untyped and psychic damage in one blow? What if another creature gave it some mixed resistance? (It happened in my game)

Additionally, some answers may indirectly encourage using whetstone to bypass resistance, or gaining resistance may increase received damage, or make it difficult to decide what type of damage did the target receive (some effect is only triggered by specific damage type).

By calculating immunities, resistances, and vulnerabilities independently for each damage type, you keep you sanity while getting believable result.

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You put a decent amount of effort into this answer, even including examples, but it is not supported by the rules as written, and it is difficult to believe it was the designer's intent. Might make for an interesting house rule, however resist-all is already crazy powerful. – Justin W May 20 '14 at 16:40
@JustinW I'd say the other way would tip the balance towards extra damage (including whetstones), which is more abundant than resist all. – Sheepy May 21 '14 at 2:08
@JustinW I've edited the answer to explain how I understand RAW to come to my conclusion. Hope it will improves the answer. – Sheepy May 21 '14 at 3:29
Un-downvoted due to fixes. – Justin W May 21 '14 at 21:16