Gwyrdallan wrote:
Do the composite blasts that are half one physical damage type and half another physical damage type get hit twice by Damage Reduction?
Not usually, no. Even if they had two different sources of DR, let's say they naturally have DR 10/piercing from their race and a magic amulet that gives them DR 10/bludgeoning, that seems to combine to DR 10/bludgeoning and piercing (meaning the attack has to count as both).
The issue here is that, unlike a weapon, the blast deals half damage that counts as (in this example) bludgeoning and half damage that counts as piercing. Not damage that is bludgeoning and piercing.
Gwyrdallan wrote:
For Example Let's say I'm using Autum Blast (any two of bludgeoning, piercing, and slashing (half each)) against a foe with 10 DR and I roll 40 damage.
So here (for this example), it's dealing 20 bludgeoning and 20 piercing.
The DR 10 applies to the whole thing, reducing it to 30 damage.
It a creature had DR 10/bludgeoning, the 20 bludgeoning would never be affected (because it bypasses), but the 20 piercing would be reduced by 10. This means 30 damage. The only importance of this difference might be if you're fighting a creature like a slime or something that reacts or splits or something when taking a certain amount of a damage type.
If a creature also had an ability that said something like, 'Takes half damage from bludgeoning attacks, then the 20 bludgeoning would be reduced to 10 (30 total) and their DR would reduce it by another 10 to 20 damage.
This would be case if the blast was half piercing and half fire or something, then the DR and any fire resistance would apply, but only up to those amounts. If a blast dealt 10 piercing and 10 fire against a creature with DR 5 and fire resistance 20, it would take 5 piercing and no fire.
Gwyrdallan wrote:
As a follow up, if the damage reduction is bypassed by one of the two damage types does it still apply to the other half?
A weapon, like a morning star, which counts as both bludgeoning and piercing would bypass it, since all the damage dealt is both of those. If the damage itself is a type, then those points of damage may be blocked even if simultaneous damage of another type is dealt and not affected.
With a composite blast, it deals specific amounts of damage, each with a certain type (like how flame strike deals half divine and half fire). In this case, just because some bludgeoning damage is stopped, doesn't mean the piercing is stopped or affected.
