Do vulnerabilities stack?

[logopolis]

I got a ruling from Wizards customer support. Looks like TheLordWinter is doing it correctly.

1) What happens if a target has several vulnerabilities to a single attack? Do they all apply, or does only to greatest vulnerability apply?

-- They all apply. In your example, Lance of Faith would do +10 damage.
​

2) A wizard is fighting a monster with cold vulnerability 5 and fire vulnerability 5. The wizard hits the monster with Frostburn (cold and fire damage). Does the monster take +5 or +10 damage?

-- When the damage of a power is described as more than one type (like the Frostburn), divide the damage evenly between the damage types (round up for the first damage type, round down for all others) For example a power that deals 25 Fire and Cold Damage, deals 13 Fire damage and 12 Cold damage. Since the monster has vulnerability to both damage types, it would take an additional 5 damage for EACH vulnerability totaling +10 damage.
​

 

[HighTemplar]

I'm afraid I don't remember where I read this, but what I'd been doing is dividing damage in half when it has multiple keywords and applying the damage to each keyword that way. So in this case if you used lance of faith and it inflicted 6 damage, it'd do 3 radiant (+5 vulnerable for a total of 8 radiant) and 3 your damage (+5 vulnerable for a total of 8 other sundry damage). When dealing with an attack with multiple keywords against a monster with resists, this is also how I do it.

Hope it helps!

This is exactly how it worked before the errata, now it dosen't work like that anymore. as per:

Keywords [Revision]
Player’s Handbook, page 55
Replace the second and third sentences of the fourth paragraph with the
following: “Also, resistance doesn’t reduce damage unless the target has
resistance to each type of damage from the attack, and then only the weakest of
the resistances applies. For example, a character who has resist 10 lightning and
resist 5 thunder who takes 15 lightning and thunder damage takes 10 damage
because the resistance value to the combined damage types is limited by the
lesser of the two resistances.”​

​

And Sorry OP I did miss your point. I though you were asking if vulnerabilities stacked.

For additionnal vulnerabilities, like vulnerable all, or vulnerable to your attacks, I don't think they were meant to stack, but then again in my game, a Vampire that got hit by strand of fate hit by a radiant attack did get +27 dmg, so I guess it comes down to your judgement until someone quotes the correct line ^^.

If what you werre asking was: If I give a creature (that has vulnerable fire 5), vulnerable lightning 5, and I attack him with a power that does 10 fire AND lightning damage, how much damage does the monster take.

Mathematically, it makes no sense to stack vulnerabilities.
Let me demonstrate(lol). You hit the said(vul 5 fire and vul 5 lightning) monster with a PBnJ sandwich. Considering your PBnJ sandwhich is as big as a solely Peanut butter sandwhich, or a solely Jelly sandwhich, (10lightning dmg is as much damage as 10 fire dmg or 10 fire AND lightning dmg) Then, everything thats not peanut butter in your sandwhich is actually jelly, and the monster is equally vulnerable to those substance so it does not matter what proportion of jelly you got. the monster is just allergic to that substance whaveter the substance.

If the monster was vul 10 fire and vul 5 lightning, Then I guess it makes sense to use only it's biggest vulnerability. Although I guess the average would make more sense, it will never be applicable in dnd4e.

 

[logopolis]

I thought you were asking if vulnerabilities stacked.

Yeah, you're right. Now that I look at it again, the thread title is a bit unclear.

Mathematically, it makes no sense to stack vulnerabilities.

This is true in 3E, but not in 4E because of the change in the vulnerability rules.

In 3E, certain damage types can do +50% or +100% damage (double damage) to vulnerable creatures. Using your example of a creature that's very weak to fire (+100% in 3E) and somewhat weak to lightning (+50% in 3E), it would make sense to hit it only with fire.

3E example: Monster has +100% fire vulnerability and +50% lightning vulnerability. A 20 point fire attack deals +20 damage, but a 10 point fire and 10 point lightning attack deals only +15 damage.

However, in 4E, the extra vulnerability damage is dealt if the target takes even 1 point of the damage that it's vulnerable to. Assuming that we accept the information given by Wizards Customer Service (in the post above), a single attack can indeed hit multiple vulnerabilities, so it makes sense to hit multiple vulnerabilities with a single attack.

4E example: Monster has fire vulnerability 10 and lightning vulnerability 5. A 20 point fire attack deals +10 damage, but a 10 point fire and 10 point lightning attack deals +15 damage.

 

[HighTemplar]

You ninjaed me on that one !

I guess CS solves it. this forum is useless !

 

[logopolis]

this forum is useless !

Not so. You don't get random food metaphors from Customer Service.

 

[Mathew_Freeman]

Not so. You don't get random food metaphors from Customer Service.

But occasionally they're able to back up what people in the rules forum say.

I'm glad I had my interpretation of the rules correct, as it seemed to make the most sense to me.

 

[Jhaelen]

I'm glad I had my interpretation of the rules correct

Did you, though?

It still surprises me, how much faith is put in CS answers.
IME, ask them the same question three times and you'll get four different answers.

 

[logopolis]

IME, ask them the same question three times and you'll get four different answers.

True, but in this particular instance, the Customer Service response makes sense to me.

 

[inkmonkeys]

Not so. You don't get random food metaphors from Customer Service.

We should fix that.

 

[deleteme123456]

But the CS response to the 2nd question should be invalid due to current errata (or should I say updates). You no longer divide the damage into separate "fire" and "cold", it's all just "fire and cold" and I would rule that a vulnerability to either is sufficient (but you need resistance to both) but vulnerabilities to both don't stack (use the higher) because there aren't separate damage types hitting you. CS is not a definitive authority sadly, since they can't even follow their own updates (unless that response predates the update that changed that, but in that case, the question should be reasked).