Assaulting Immunity

Dominic Matte

Lately I've been thinking about monsters with immunity or resistance to a certain damage type.

Immunity to a certain damage source makes sense in a lot of situations. The dragon that lives inside an active volcano and bathes in lava isn't going to worry about, say, stepping in a campfire. It makes an equal amount of sense that such a dragon could easily shrug off a wizard's fireball. Or, coming from a different direction, it makes sense that a gelatinous cube is immune to a sneak attack that targets a creature's vital areas.

On the other hand, it isn't fun.

Damage immunities reduce the number of options available to the party. You might say that a pyromancer fighting a fire elemental should look for alternatives, like finding the tome that will banish the elemental, or locating the brazier that controls it. But those options can coexist just fine alongside the option to attack. This is just basic math: two options vs. three options.

Now, I'm not saying that a character who chooses to specialize in fire damage should always be equally effective against everything. However, there are plenty of ways to reduce a character's combat effectiveness, or force him to consider other tactical options, without telling him he can't damage the monster at all ever.

Monster Manual 3's volcanic dragon is a perfect example. Instead of fire resistance or immunity, the dragon has a power called Sudden Flare: whenever it's dealt fire damage, each enemy within its aura takes poison damage. Instead of telling Bob the Pyromancer that he can't deal damage to the dragon, you're telling him that he needs to be careful about when he attacks the dragon, and should look for other options if he doesn't want to hurt his friends. He can also coordinate with his party, having them move out of the aura temporarily to allow Bob to make some big attacks without damaging the player characters. This is way more fun than immunity. Instead of telling your players what they can't do, you're adding complexity and depth to the encounter.

Even worse is the undead's immunity to sneak attacks. While technically the sneak attack description does mention vital organs, shouldn't it be easier to sneak attack an unintelligent, unaware creature like a zombie or a skeleton? Not to mention that sneak attack is a core class feature of the rogue - it's one thing to tell Bob he chose the wrong spells, but quite another to tell Steve he chose the wrong class.

Immunity doesn't just punish powergamers who should've known better than to overspecialize. It punishes the guy who took simple fire spells because he's just trying a wizard for the first time and doesn't want to be overwhelmed. It punishes the guy who took mostly fire spells to match his wizard's personality, which by the way, means punishing a player for good roleplaying.

Yes, a good DM can plan a complex encounter against a monster with immunities that keeps everyone involved. But not every DM has enough experience to do so, and not every player cares for layers-deep tactical combat. Getting rid of immunity in favour of special powers that trigger on X damage type increases the number of options available to the players while still maintaining the idea that it's not wise to attack a volcanic dragon with a fireball.

On a subtler note it also opens up the possibilities for paragon paths / prestige classes / whatever a little bit. 4e had sorcerer paragon paths specializing in a certain elemental damage type, and each of them had a class feature that allowed them to overcome resistance to that damage type. It makes sense but it's no fun. Really all it does is say "now you can damage ice elementals as if you had taken lightning spells". Instead you could get some cool power boost or maybe even a reaction power to cold damage for yourself.

If for some reason we really absolutely must keep resistances/immunities, I'd much rather see immunity thresholds. If the fire elemental takes less than X fire damage, it ignores the damage completely. If the elemental takes more than X fire damage, it takes all the damage. This could satisfy those who think the elemental should have some kind of resistance stat to survive in a volcano, and it would also allow any character to overcome the immunity if they put enough work into it.

But I really would rather rid the core rules of immunity entirely and have it live on in the hands of the DM if/when they think it's appropriate, replacing it with cool things like the volcanic dragon's Sudden Flare. When I give the pyromancer a hard time, I want to throw a wrench in his plans, not a sledgehammer.

How do you feel about immunities? Do you think they should stay as-is, or do you prefer the reaction power approach?