Adding Monster Vulnerabilities

[HamsterKun]

Do any of you guys add vulnerabilities to monsters in your campaigns?

[Man_Over_Game]

Do any of you guys add vulnerabilities to monsters in your campaigns?

Lots. Especially related to weapon damage, to reward players for being more diverse and planning ahead.

I make Zombies weak to Fire damage and resistant to Cold, and Skeletons weak to Bludgeoning but resistant to Piercing. Little things like that.

For Humanoids, I actually use Dwarf Fortress as a foundation: Bludgeoning Weapons are good for armored units, Slashing Weapons are good for unarmored units, and Piercing Weapons are balanced between both. As a result, heavily armored creatures have Vulnerability to Bludgeoning damage and are resistant to Slashing damage, and unarmored creatures have Vulnerability to Slashing damage and are Resistant to Bludgeoning. I only ever impose this on enemies/NPCs; I would not advise modifying players' resistances/vulnerabilities willy-nilly.

This also incentivizes players to be more generalized than specialized. Sure, you could invest in PAM and GWM, but don't expect the same tactics to work every time.

[MrStabby]

Adding to existing monsters? Only rarely.

Generally vulnerability can blow balance. Casters that can bring to bear six or seven different damage types will tend to benefit a lot more than a fighter that might have a weapon and a back-up weapon to chose between.

So yeah, sometimes... but be careful.

[Bubzors]

Lots. Especially related to weapon damage, to reward players for being more diverse and planning ahead.

I make Zombies weak to Fire damage and resistant to Cold, and Skeletons weak to Bludgeoning but resistant to Piercing. Little things like that.

For Humanoids, I actually use Dwarf Fortress as a foundation: Bludgeoning Weapons are good for armored units, Slashing Weapons are good for unarmored units, and Piercing Weapons are balanced between both. As a result, heavily armored creatures have Vulnerability to Bludgeoning damage and are resistant to Slashing damage, and unarmored creatures have Vulnerability to Slashing damage and are Resistant to Bludgeoning. I only ever impose this on enemies/NPCs; I would not advise modifying players' resistances/vulnerabilities willy-nilly.

This also incentivizes players to be more generalized than specialized. Sure, you could invest in PAM and GWM, but don't expect the same tactics to work every time.

Same here. I do it all the time. I honestly feel that physical resistances are kind of dumb in how they are implemented in 5e. The monster is only resistant until the party gets magical weapons. So realistically only resistant until level 5ish then it doesnt matter anymore. Which is simple and quick but doesnt really add anything to the game

[HamsterKun]

I add vulnerabilities myself when I DM. I also add an additional damage type in conjuction with the Elemental Evil Player's Companion: Wind.


All Monstrosities are weak to Fire, Cold, Lightning, or Wind, making them the four primary damage types.
Undead are almost universally vulnerable to Radiant and absorb Necrotic, and are usually weak to Fire and resist Cold.
Flesh, Clay, and Stone Golems are all weak to Wind.
Celestials and Abberations are generally weak to Necrotic; Fiends and usually weak to Radiant.
If any creature is insane for some reason or another, they are weak to Psychic damage. (if they're mind's broken, they're left pretty much defenseless to any mental attack launched at them)


And so on, so forth.

[Xihirli]

Not so much vulnerabilities as special debuffs that happen when certain damage types are used. Like flesh golems with fire, only less extreme. I want to show my players (mostly newbies) how useful status effects can be in ways other than just inflicting them onto them.

[DrKerosene]

I make (snip) Skeletons weak to Bludgeoning but resistant to Piercing.

Do you mean Flameskulls, Mummies, and Gnoll Witherlings? Otherwise you’re just adding a damage resistance there. I don’t think any “skeleton” creatures doesn’t already come with a racial vulnerability to bludgeoning.

I haven’t homebrewed any Vulnerabilities that weren’t already official, but I’ve been wanting to use more of those narrative “weaknesses” like banishing a Barghest with enough Fire, or the Froghemoth being auto-slowed by Lightning damage (despite being actually Resistant to the damage).

[Black Jester]

Adding resistances is just as legit, if not moreso, as adding more weak spots. Especially if they are dictated by logic, like a skeleton's resistance to piercing damage, or the traditional immunity of mindless undeads against illusion and enchantment spells.
By adding more resistances, you force the players to think more out of the box and develop better tactics instead of using brute force to push through most encounters.


The important part is that the players have a reasonable way to figure out these abilities by the way the creature and their environment is represented, and that the internal logic of the setting as a whole is always kept as the central element.

There is also no issue whatsoever to retroactively add a weakness to a monster if the players have logically and convincingly concluded that they really, really should have it - like a vulnerability to cold damage for reptilian Lizardfolk and Yuan-Ti or that siccing a pet rust beast on a modron collony would result in an annihilating carnage. Rewarding the player's creativitiy is more important than strictly sticking to the book.