Why Don't Different Types of DR Stack?

[Hrothgar Rannúlfr]

From the SRD:

Damage Reduction
...
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.​

We're working on creating a warlock and we came up with a question about diffterent types of damage reduction not stacking.

What is the "in game" reason that different types of damage redution don't stack?

We're using the Armor as Damage Reduction variant from Unearthed Arcana. The Warlock is wearing armor that provides 2/- damage reduction. And, we're trying to understand the "in game" reason that his 1/cold iron damage reduction doesn't stack.

Thanks in advance!

 

[Starbuck_II]

I think it was a power issue: worries about being too hard to hurt.

In game: because they protect vs different things. Having multiple times prevents one bypassing it without damage alone.

Altough DR/- should stack since nothing bypasses it anyway (thematically to me).

 

[BENINHB]

DR usually doesn't stack but it does overlap and cover each others weakness.

So DR2/silver and DR2/magic do not equal DR4 but they do overlap, so a weapon has to be both silver AND magic to get through the DR. One or the other isn't going to cut it.

 

[Bendraesar]

It's probably an example of Wizard's idiotic damn game making.

DR 1,000,000,000/- won't save a monster from an Evoker let alone a God Wizard or any other Tier 1 class.

 

[orion90000]

From the SRD:

Damage Reduction
...
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.​

We're working on creating a warlock and we came up with a question about diffterent types of damage reduction not stacking.

What is the "in game" reason that different types of damage redution don't stack?

We're using the Armor as Damage Reduction variant from Unearthed Arcana. The Warlock is wearing armor that provides 2/- damage reduction. And, we're trying to understand the "in game" reason that his 1/cold iron damage reduction doesn't stack.

Thanks in advance!

At the bottom of that page it gives an example of a frost giant barbarian wearing armor:

Finally, a frost giant has a +9 natural armor bonus, so it gains DR 1/- from natural armor. The chain shirt it wears gives it an additional DR 2/-. If the frost giant were a 7th-level barbarian, the barbarian class levels would give it DR 1/-. These three values add up to DR 4/-. The giant’s AC would be 20 (10, +8 natural armor bonus, +2 chain shirt).

So, under the version you are playing, DR derived from armor would stack with other types of DR.

 

[TanisFrey]

Unearthed Arcana is a 3.0 book so, unless you are using the Armor as Damage Reduction variant rule, DR does not add together.

If you use both 3.5 rules and the Armor as Damage Reduction variant rule, your DM needs to rule how they interact.

I suggest that you add up the DR X/- and you get one additional DR. You would get which ever DR type is best under the circumstance of the attack. This suggestion would be a house rule, if you use it.

 

[bastrak]

Having been published in 2004 Unearthed Arcana is a 3.5 book.

 

[Bendraesar]

Having been published in 2004 Unearthed Arcana is a 3.5 book.

That and the link was from the SRD, which as far as I know is all 3.5 material (I think they have the updated versions of 3.0 stuff on there like rules on Deities and Demigods).

 

[irdeggman]

Other than the armor as DR variant (and posts referring to the text for clarification) some DRs do stack (if specifically stated).

for example Fey Skin (from Complete Mage) specifically states that its DR/cold iron stacks with DR from other sources like class and race (it is pretty much a warlock or sorcerer preferred feat chain.

 

[DumbPaladin]

There's also a Armor Crystal in Magic Item Compendium that grants DR 1, 3, or 5 / -- that stacks with similar DR from another source.