The Problem of Immunity (Rules Musings)

24 March, 2012

Burn it!

It won’t burn?

What, not even magical fire?  But it is such a little monster.

In Pathfinder (like 3.x before it), there are a number of monsters, and some classes, that gain flat and total immunity to a variety of things.  This was brought back to my attention by the comments on my review of the Genius Guide to: Fire Magic and has been discussed as a problem by Sean K Reynolds (and possibly others).

Immunities are just no fun, not for the player, not for the GM, not do they make a lot sense.  Sure, the King of the Fire Elementals cannot be harmed by fire, that makes sense.  But should not a 2HD small fire element be washed away by a powerful enough gout of flame?  Cannot a creature of electricity be ionized if overwhelmed by a massive stroke of lightning?

I am thinking of setting “immunity” to damaging effects as equal to Resistance 30 or HD x 4 (whichever is higher for each individual creature), enough to shrug off small effects but a big enough fireball can still blast away the smaller of the fire elementals, powerful enough cold will still freeze a yeti and so on.  The exception would be the vanishingly rare creature (like the afore mentioned Elemental King) who would have True Immunity, that does ignore all such damage.

So elemental damage immunity becomes a short hand for “really hard to damage in this way” rather than “pack up your fireballs, you are going home dead.”

Now, other immunities, like the Paladin’s immunity to fear or the Druid’s immunity to poison and even the construct’s immunity to sneak attacks.  The first set reduce the number of interesting tricks the GM can use against the player characters, the second penalize certain classes and makes the game less fun for their players.

As I have been working on adjusting the fear rules,  I wanted to scale down the Paladin’s immunity to fear while still making them exceedingly brave (Reynond’s suggests giving them a +10 fear save, but that seems to bland), so I am thinking of using this:

Aura of Courage (Su)

At 3rd level, a paladin becomes highly resistant to fear (magical or otherwise), she ignores affrighted penalties up to half her level (rounded up) or her Charisma modifier, whichever is lower, suffering penalties only from the amount that exceeds their resistance.

Each ally within 10 feet of her gains a +4 morale bonus on saving throws against fear effects. This ability functions only while the paladin is conscious, not if she is unconscious or dead.

I have already addressed sneak attack damage to some extent in my house rules as to the other class based immunities, still pondering what to do with them.  Immunity to diseases, at least non-magical ones, does not seem like a major issue.

What do other people think?  Have you had problems with immunities in your campaign?  What solutions have worked for you?

Updates: Read more an this issue at Keith J Davis – In My Campaign and Harbinger of Doom.


  1. No, a 2HD Fire Elemental ought to be transformed into an 8HD Fire Elemental by a big enough gout of flame.

    • One could rule that adding a like element to an elemental simply grows the elemental. However, this would presume that there is no distinction between the inanimate, magically created fire of a fireball and the living, supernaturally endowed fire of a fire elemental. This would be roughly equivalent to stating that spraying a cow with ground beef should result in a bigger cow.

      This would then create the necessity of a subsystem (or at least a rather detailed chart) specifying just how much of a size increase an elemental gains for varying amounts of their element they encounter.

      Another problem would come up when an elemental, no matter how small, interacts with their element in the environment. Applying the above logic, the flames created by a 1/2 HD fire elemental burning a house should increase the elemental’s size considerably to a 8-10 HD Elemental at a minimum. Since this ability can be performed by any fire elemental, the CR and even stats of fire elementals becomes somewhat invalid as even the smallest fire elemental has the potential to become as large as the largest amount of flammable material in the setting. Similarly, water elementals are always more dangerous near wells, rivers, oceans, rainy days, etc, an air elemental has a functionally infinite CR rating, earth elementals can draw upon the mass of an entire planet to boost themselves to a CR of sheer ridiculousness.

      Even if one adds to this ‘like begets like’ subsystem a set of restrictions specifying the rate and upper limits of their absorbent abilities, the problems still remain, but are simply doled out in a set of ranges rather than a single range.

      Personally, I’d recommend against this entire line of reasoning as it seems to result in more problems than benefits for both the GM and the players.

      • Very thoughtful and interesting point there. Though I think there is a place for elementals that can grow, and use favorable environments to their advantage, but you are perfectly correct that it needs to be constrained.

        In other words, a full growing/consuming elemental should be a major plot point not just something that always happens. Elementals as weapons of mass destruction?

  2. Sounds reasonable.

    Longer response at http://www.kjd-imc.org/2012/03/24/no-more-fears-or-fire-damage/

  3. I’m pretty sure if a player in my group tried to do something like cast a fireball at a fire elemental he would be in contention for “ye olde junk punch.”

    • Sometimes you have to work with what you have. Also, elemental specialist mages are a genre staple, should they just be useless when the wrong sort of monster appear?

  4. I see nothing wrong with this concept.

    Who is to say that the magical fires evoked from the casting of a fireball are in any way similar to the fires with which the fire elemental draws to make its body?

  5. Our group calls this the golem problem, after 3.5 golems. They are immune to magic, except for specific spells. They are immune to critical hits and sneak attacks. They have damage resistance and lots of hit points. The only basic archetype that can deal with them is a fighter who used big two-handed weapons.

    And there are two schools of thought. One is that challenges that nerf specific types of characters suck and should be removed or limited in the game. One is that challenges that nerf specific types of characters forces the players to become more creative and figure out something to do without using their big trick.

    Removal/limitation also has a couple of different issues. When and how do they remove it. In 3.5, the game was built around certain types of limits. Rogues can only sneak attack living creatures with defined anatomy. Fire creatures are immune to fire. However, later supplements eroded those limits. Spells, items, prestige classes – you could find a way around nearly any limit. Which potentially breaks the balance of the game and allows for some pretty gross builds. 4e largely removed these limits in the design phase. While it works well, some people think it makes the game feel bland.

    Solving this by being more creative is a good idea in theory, but in practice it often makes people feel a little useless. Sometimes you can’t come up with any way to help. If you face a lot of this, you end up feeling that your character is just a spear-carrier in the story.

    I like your idea of saving true immunity for big bosses, and changing lesser immunity to big resistances. I could also see this as a damage divider. The fire elemental only takes 1/4 damage from fire attacks.

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