Do vulnerabilities stack?

[logopolis]

If a target has multiple vulnerabilities to a single attack, do they all stack?

For example: Let's say a cleric is fighting a zombie (radiant vulnerability 5). The cleric hits the zombie with Cascade of Light, spends an action point, and then hits the zombie with Lance of Faith.

The Lance of Faith does radiant damage, and the Cascade of Light gives the zombie vulnerability 5 to all of the cleric's attacks.

Does the Lance of Faith do +5 or +10 damage?

 

[Zsig]

I'm not sure about the right answer, but think about it the other way around.

If you hit a monster with Resistance against 2 different types of damage with an attack that deals both kinds.

Do you reduce the damage twice, or only once?

IMO, the answer to both your question and mine is "do it once".

 

[Mathew_Freeman]

If a target has multiple vulnerabilities to a single attack, do they all stack?

For example: Let's say a cleric is fighting a zombie (radiant vulnerability 5). The cleric hits the zombie with Cascade of Light, spends an action point, and then hits the zombie with Lance of Faith.

The Lance of Faith does radiant damage, and the Cascade of Light gives the zombie vulnerability 5 to all of the cleric's attacks.

Does the Lance of Faith do +5 or +10 damage?

I'd say that this is an excellent example of how to put two abilities together, and that it does +10.

The zombie has two seperate vulnerabilities, and you happen to be hitting both of them, so it stacks.

 

[HighTemplar]

Now this took a little bit of research, but the answer was obvious, only the bigger number applies. Giving vulnerable 10 radiant to a monster that already has vulnerable 5 gives him vulnerable 10. Giving vulnerable 5 to a monser that already has vulnerable 5 does not make him additionnaly vulnerable.

Immune/Resist​

​

​

/Vulnerable: Add the stated
entries and values. If the monster already has one or
more of these abilities, use the more beneficial value.​

Now this might not be the EXACT answer you're looking for, but I'm sure you get the point.

Duplicate or Conflicting
Monster Abilities

​

When you a overlay a template on a monster, you simply
add the template’s abilities and powers to those the monster
already has. Sometimes, though, these powers and
abilities contradict or duplicate previously existing ones.
The basic rule in such situations is that numeric values
of duplicate abilities are not cumulative.​

I understand you're not applying a monster template, but I'm certain that using powers applies the same way. Perhaps the EXACT answer your looking for is written somewhere but I can't find it.

Maybe think of it as an allergy. If you're allergic to peanut butter, and I use a magic limited wish to make you allergic to peanut butter, you become allergic to peanut butter, whether you already were , or not. If I used a more potent real wish to make you SUPER DUPER allergic to peanut butter, then you become SUPER DUPER allergic. Nothing states that you should become more allergic if you already were, I guess this is the 4E way.​

 

[logopolis]

Maybe think of it as an allergy. If you're allergic to peanut butter, and I use a magic limited wish to make you allergic to peanut butter, you become allergic to peanut butter, whether you already were , or not. If I used a more potent real wish to make you SUPER DUPER allergic to peanut butter, then you become SUPER DUPER allergic. Nothing states that you should become more allergic if you already were, I guess this is the 4E way.

I like your analogy, HighTemplar!

Unfortunately, the template resistance rules don't quite answer the question because the OP involves two separate "allergies".

To continue your analogy: Say you're allergic to peanut butter. Then, instead of casting a spell to make you more allergic to peanut butter, I cast a spell to make you allergic to jelly as well. What happens if I hit you with a peanut butter and jelly sandwich? Do you suffer the negative effects of peanut butter + the negative effects of jelly, or does only the worse effect apply?

 

[The Little Raven]

If a target has multiple vulnerabilities to a single attack, do they all stack?

For example: Let's say a cleric is fighting a zombie (radiant vulnerability 5). The cleric hits the zombie with Cascade of Light, spends an action point, and then hits the zombie with Lance of Faith.

The Lance of Faith does radiant damage, and the Cascade of Light gives the zombie vulnerability 5 to all of the cleric's attacks.

Does the Lance of Faith do +5 or +10 damage?

They do not stack. The highest value is the one applied. If a zombie has vulnerability 5 radiant and you give him vulnerability 5 radiant, his vulnerability remains at 5 radiant. If you were giving it vulnerability 10 radiant, then it would have vulnerability 10 radiant instead, as 10 is higher than 5.

If you hit a monster with Resistance against 2 different types of damage with an attack that deals both kinds.

Do you reduce the damage twice, or only once?

From the errata: “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.”

So, you have to have resistance to both damage types, and only the weakest resistance applies.

 

[DracoSuave]

But we're not adding vulnerable radiant 5 to vulnerably radiant 5. We're adding vulnerable raidiant 5 and vulnerable everything 5, which is a totally different anology. Like what happens if you have a swarm with vulnerable area attacks 5 and you hit it with vulnerable everything 5?

Also, adding a template to a monster does not answer the question of multiple vulnerabilities in combat. The monster doesn't -have- the same vulnerability twice, in this question. It's two seperate vulnerabilities that both apply to the same attack, and the PHB is mum on the subject.

 

[Mathew_Freeman]

But we're not adding vulnerable radiant 5 to vulnerably radiant 5. We're adding vulnerable raidiant 5 and vulnerable everything 5, which is a totally different anology. Like what happens if you have a swarm with vulnerable area attacks 5 and you hit it with vulnerable everything 5?

Also, adding a template to a monster does not answer the question of multiple vulnerabilities in combat. The monster doesn't -have- the same vulnerability twice, in this question. It's two seperate vulnerabilities that both apply to the same attack, and the PHB is mum on the subject.

Which is why I would rule that they stack.

The two vulnerabilities are "radiant 5" and "attacks from that cleric 5" - surely this is exactly what the power was meant to do?

 

[TheLordWinter]

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!

 

[Xris Robin]

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!

Isn't that just how it worked before errata or something?