So Phil, the ChattyDM, chronicles a battle over at his site wherein he forgot about a plant creature’s critical hit immunity, and let it slide as a “nice DM” bonus.
See??? Even DMs who know the rules forwards and backwards forget this rule. Cast thee out, I say! Critical Hits for all!
and I began a mini-rant, which I shall continue here.
The way I figure it, plants, oozes and constructs are a minority of what we fight in D&D. The only crit-immunes that are very common are undead.
But most undead, IMHO, should be crittable anyways. Has nobody seen the lucky headshot in a zombie movie? Or the stake to the heart in a Buffy episode? With the possible exception of skeletons and incorporeal undead, most undead are shown as having more damaging areas.
So why not allow crits for everything?
And don’t say to balance rogues. A rogue’s job is to get in, strike quick, and do good damage. Crit-immunes don’t balance rogues, they nerf rogues for that encounter. Same as a golem’s magic immunity does to casters.
Now, being useless for an encounter is no fun.
Similarly, scoring a natural 20 (ankle bite or not), and not being able to use it, is also no fun.
Yet for some reason, some people don’t want to throw out crit-immune creatures altogether. So it seems a house-rule compromise is necessary.
Well the compromise between crit-immune and nothing is crit-resistant. But we have no mechanic for crit resistance, so that’s what we’re going to need to devise.
Anatomy of a critical hit:
- Attack roll
- Critical threat range
- Damage multiplier
Any one of these stages can be where the resistance comes in. Now to tackle them completely out of order.
Stage 1: Attack roll
Probably not the best location. This stage doesn’t make them harder to crit, specifically, though hitting less does mean critting less. No to this one.
Stage 2: Critical threat range
Not bad. One option is to reduce the crit range by 1 against crit-resistant creatures. Think of it as an inverse Keen. This will reduce the chance that a hit is a crit by 5%, and for most weapons will halve the amount of crits achieved. One major problem arises, however, with axes, hammers, bows, and many simple weapons with crit ranges of 20, eliminating the possibility of crits altogether. And when a scythe can’t crit a zombie, something’s wrong.
Stage 5: Damage multiplier
Similar to threat range, reduce by 1. Similar problem as well, where a greatsword’s crit multiplier becomes x1. Nope.
Stage 4: Damage
This one is a possibility. Reduce crit damage, similar to DR. But the number needs to be chosen carefully. Too small, and it’s negligible. Too large and a crit may do less damage than a non-crit from the same weapon. Too tricky for my tastes.
Stage 3: Confirmation
Now this is where we want to be. Confirmation is what decides how difficult it is to crit someone, while never eliminating the possibility of a crit, or changing the likelihood of hitting them.
So how do we do it, though? We could give crit-resistant creatures a bonus to AC vs crit confirmations. +4/+5 might be good. Perhaps the bonus should scale based on the level/CR of the creature? No, the creature’s AC (and thus the required confirmation roll) already scales with its level. And more to the point, what sort of scaling is best? CR? HD? 1/2 CR? 1/3 HD? I have no idea.
No, for this house rule I’m going to take a page from the Star Wars: SAGA edition RPG. Modifiers are extra math and new AC values require an extra space in a stat block. Thus I propose the following:
When confirming a critical hit against a crit-resistant creature, roll your attack roll twice, and take the lower of the two rolls.
This makes these creatures more difficult to crit against. The exact difficulty of scoring a crit will scale with their AC (and thus their CR).
Now what about Rogues? Are they allowed to sneak attack with impunity?
Well, I believe that anything that can be caught unaware (denied dex) should be sneakattackable. But for those who want to represent these creatures’ crit-resistances, I would propose this house rule:
Sneak Attack and Crit-Resistant Creatures:
Sneak Attack (and Skirmish, Sudden Strike, or any other precision-based damage bonuses) add only half the bonus they normally would, rounded down, against crit-resistant creatures.
I’ll leave this up to the individual GM to decide whether that means half the damage dice (+7d6 becomes +3d6) or half the damage (more math, +7d6 becomes +((7d6)/2)). Straight bonuses (+5 damage) would be halved and rounded down (+2 damage).
What do you think?