Damage cap thought experiment

A recent thread about Heavy Armor Mastery got me thinking. It's mostly good at lower level when it stops a higher percentage of the damage. When you have a CR 8 frost giant hitting for 3d12+6 it's not a big deal.

One issue with HAM style "DR" (vs. Resistance which just halves the damage) is that it applies the same regardless of how many dice of damage are getting rolled, so it doesn't scale well at all. It's either too powerful or too weak.

So I was thinking about the far side of HAM - a damage mitigation feat that's more useful at high levels. Well, standard 5e Resistance already is, but I was thinking more like HAM - markedly better against high threat foes then against a bunch of low threat foes.

Which came up with the idea of a feat that caps damage for any single hit. For example, if it capped it at 30 and you were then hit for 44, 12, and 166, you'd take 30, 12, and 30 instead.

There's no narrative to that, it makes no actual sense and I'm not suggesting it in-game. But as a thought experiment it becomes interesting.

And that brings up a few questions. Please answer them assuming point buy/standard array so we have a common value for an ASI vs. a feat. Also I'm assuming the non-fighter/rogue ASI advancement in asking the questions below.

1. What would the worst it would be (highest cap) where it would become a "must have" at 16th when you're getting your 4th (or more) ASI. So you have a 20 in your primary, some other ASI or feat, and you are facing foes in last tier of play. Where would it have to be in order to make it "must have"?
(This is also the "it definitely breaks here" limit, where anything better (lower) than this won't fly.)

2. Same conditions, but make it an interesting choice on-par with the rest of your "second choice" feats. So on par with something like Sentinel or Warcaster or something like that when you already have your first choice feat.

3. Same concept as #2, but instead think 12th level (so lower monster damage climbing as your level), and a reasonable contender for your first feat.
(How does this compare to #1?)

4. With the levels from #2 and #3, are there any conditions you'd consider taking it as one of your first two ASI/feats?

Thanks for your brain cells.

Big hits are kinda necessary to threaten PCs at high level play, so this sounds like a god feat if you set it at a static cap (unless the cap is pretty high, which in turn makes it completely useless at lower levels). You'll also quickly become invulnerable to instant death from damage that would equal or exceed your HP max (which doesn't come up often enough at my tables to really be an issue anyway, but still).

The only way I can see making it functional is to have it scale with level. I'd probably go with half max HP if I were set on including such a feat at my table.

Just a few initial thoughts, I'm sure others will have more to add.

Nevvur said:

Big hits are kinda necessary to threaten PCs at high level play, so this sounds like a god feat if you set it at a static cap (unless the cap is pretty high, which in turn makes it completely useless at lower levels). The only way I can see making it functional is to have it scale with level. I'd probably go with half max HP if I were set on including such a feat at my table. Also depending on the cap amount, you may become invulnerable to instant death from damage that would equal or exceed your HP max.

Just a few initial thoughts, I'm sure others will have more to add.

Click to expand...

Okay, let's try this from the top.

It's not actually expected to work as a feat. I wouldn't want it in a game, it makes no narrative or game sense. Please don't try to fix it. But, it brings up interesting questions. It's a thought experiment to see what numbers make it a god feat and what merely makes it competitive.

It's completely understood and discussed that it's no good at low levels, just like Heavy Armor Mastery isn't good at high levels. Please, that's why all of the questions are at high levels.

Let's focus on this bit:

Nevvur said:

...this sounds like a god feat if you set it at a static cap (unless the cap is pretty high...

Click to expand...

I have these questions about WHAT the cap should be - the worst (highest) it's still considers a must-have (a "god feat" as you put it), and then where is it high enough that's it's worth thinking about, but not a must-have. With level ranges - the first two questions are at the 16+ range of play, the third is at 12+.

So your point cuts right to the quick of what I was asking - what are those caps?

Would it be physical damage, or any damage? Monsters that are big in melee tend to more hits, rather than just bigger hits. Big T's biggest hit only averages 36. An ancient red dragon only does 21 physical on a bite (+14 fire). A storm giant does 35 physical damage with a rock. I can't find anything that does >40 physical damage with a single attack.

If it's any damage, though, the damage goes way up. Solars average 22 physical + 27 radiant per swing. Ancient Red does 91 average with Fire Breath. Big T's swallow does 56 average acid damage per turn. A disintegrate spell averages 75.

So where your cap would be would depend on if you want a high-level HAM (good against high level physical threats), or an actual "no burst damage" feat. For a high level HAM, I'd say probably 25? Serves to protect against high rolls and crits primarily, but still vulnerable to a fast, strong attacker.

[MENTION=20564]Blue[/MENTION]

I feel there's too much variation in HPs at higher levels to suggest concrete numbers on what the upper limits of the cap should be. The feature would have very different impacts on a barbarian and a wizard. That's why I didn't offer any specific numbers, but suggested looking at it from a scaling mechanic instead where it could function reasonably well. Respectfully, starting the thought experiment from a position that is fundamentally flawed will probably generate results that are fundamentally flawed. You might not see your original proposition as such, and if so, you may disregard my input.

I like DR as a mechanic in real-time games because it creates a meaningful distinction between making lots of small, fast attacks and making a few big, slow attacks: 3 DR absorbs 60% of two 5-damage hits but only 30% of one 10-damage hit. Even in games that don't use attack speed as a variable, you can get the same effect out of varying accuracy: if the 5-damage attack is twice as likely to hit as the 10-damage attack, you still average two 5-damage hits for every 10-damage hit. The thing is, 5E D&D doesn't really deal in trade-offs in either attack speed or accuracy very much. Sure, characters can get more attacks per round, but it's mostly as a flat increase in power. And bounded accuracy tries to keep everybody roughly on par there too (with the notable exception of the Great Weapon Master and Sharpshooter feats).

But let's ignore the fact that it doesn't really matter in 5E and, noting that DR favors heavy attacks over light ones, ask what mechanic would symmetrically favor light attacks over heavy ones. A damage ceiling would do it, but not symmetrically -- note that DR still does something to heavy attacks, whereas a damage ceiling does nothing to light attacks. Instead, the cleanest way I've found to do this is a "dodge" mechanic. Note that by "dodge", I don't mean a flat percentage miss chance like you see in a lot of RPGs and strategy games. I mean the ability to dodge one attack per fixed interval. If you can dodge one attack every four seconds, then you're going to avoid 50% of a 10-damage-per-two-seconds attack but only 25% of a 5-damage-per-second attack.

There is still one asymmetry, though. Perhaps understandably given its natural flavor, I have yet to see this sort of mechanic as a passive benefit a la DR. In video games, it's normally an activated dodge-roll move with a cooldown. And in 5E (where it does indeed already exist as the 5th-level rogue class feature!), it's very similar.