So for many years I've had a certain belief about how vuln stacking works, but would like to just get it straight.

Example: fighting undead that is (for purposes of this discussion) vuln to silver and vuln to holy. I use a weapon that is made of silver, and has wrath attack. Am I getting 2x vuln damage? Do they stack or is the second vuln just wasted now?

Compare with a silver weapon that is not holy attack (and is something the undead is neither vuln nor resistant to, just regular). How much damage do I do in comparison?

Compare with a steel weapon that is holy? Same question.

How do the multipliers work?

Thanks!

NO VULN: total damage = damage
VULN_HOLY: total damage = damage * 1.33
VULN_SILVER: total damage = damage * 1.33
VULN_SILVER + VULN_HOLY = total_damage = ((damage * 1.33 (silver)) * 1.33 (holy))

Stacking vulns only works when you have a material vulnerability + damage type vulnerability.

I reiterate my offer of a year or so ago: come to NYC and you drink for free.

And I'm in NYC!

They definitely stack. I'm guessing it's multiplicative, not additive, but that's a total guess. If you're hitting a vuln you're doing 4/3 what you'd do without the vuln. So two vulns would be 16/9 * normal.

If it's additive then you'd be looking at 5/3 * normal, which is not much less than 16/9.

Yeah, I "know" from my own years of experience that there is a benefit to using 2 vulns like that (the easy examples always came when I was playing a maran and had access to silver and holy and fire and physical all at once). I'm just curious and hope someone on the staff can just clear up how that works.