HP Overhaul: Injury Levels

[AverageCitizen]

So I have been thinking about HP alternatives. I'm curious as to what you guys think of this one:

Injury Levels

Damage Saves:
When you are hit with an attack, you must make a damage save. Your damage save bonus is calculated as follows:

Average of your HD roll as per class advancement (e.g. 6 for 1d10) + Con Modifier + Proficiency Bonus.

The save DC is 10+ the average damage of the attack, often listed in the monster stat block. On a successful save, you take a cumulative -1 penalty on damage saves. If you fail the save, you receive a level of injury. If you fail the save by 5 or more, you receive 2 levels of injury. If you fail the save by 10 or more, you are immediately fall unconscious and begin to make death savings throws as though you had been reduced to 0 HP.

Injury Levels

Level	Effect
1	Disadvantage on ability checks
2	Speed halved
3	Disadvantage on attack rolls and saving throws
4	Roll once on the "Lingering Injuries" table, DMG pg. 272
5	Speed reduced to 0
6	Death

Behind the scenes and next steps: So, from what I can tell as written above this variant makes the early levels easier on combat oriented characters and scales up until at very high levels the saves will be tough to make, so the scaling almost certainly needs some tweaking. Also, a lot of damage at once is dangerous, so high level spells become very deadly so that may need to be adjusted. Finally, I am not sure how healing should work, based on the logic I used to do the scaling so far it would be something like every 1d8-1d10 HP worth of healing would remove a level of injury. Temporary HP would probably best be represented as a one-time boost to damage saves.

I'd love some help and feedback, this is a rough idea so I know it will need work, but keep in mind it is MY idea and I am arrogant and love my ideas like they were my babies, so be gentle.

PLEASE NOTE: All too often posts like this turn into threads challenging the premise of the variant, and I'd really like to avoid having to justify the idea. I have some specific reasons that I think an alternative like this would be good for the game. If you can't catch the vision of it then please, just move on, I am really just hoping someone out there likes the idea and can help me hammer it out.

EDIT the first: Changed it so that you receive -1 to damage saves on a successful save instead of as the first degree of failure. I realized the numbers work out better this way and it makes it so that low-level monsters can still be a threat to higher level characters in large numbers.

 

[Sadrik]

Damage as a save rules are neat.

I think your die conversion should follow this. The monster average damage is literally the average of the die (2d6=7) roll but for your purposes this is better I think otherwise you may get some weird interactions. Fireball 8d6 becomes 32 (if 4 per die) and 24 (if 3 per die)...

d4 2
d6 3
d8 4
d10 5
d12 6
d20 10

So damage save DC is equal to:
converted damage die + STR/DEX + other modifiers or monster average damage

A damage save roll is equal to:
Armor modifier + CON + converted HD + 2*Proficiency - 20 + d20

So if you were a 1st level fighter with AC 15 armor and 14 CON, you would have:
+15 (Armor) +3 (CON) +5 (HD) +4 (2*Proficiency) -20 (+7 total) +d20 = avg. roll 18.5

If you were a 1st level wizard with mage armor AC 13 and 10 CON, you would have:
+13 (Armor) +0 (CON) +3 (HD) +4 (2*Proficiency) -20 (+0 total) +d20 = avg. roll 11.5

If you make it by 5 no effect. If you make it but not by 5 you take an exhaustion level. If you fail by 5 you take two exhaustion levels. Hmm, could shift everything by 5 more to account for this better.
equal or greater - no effect
For every 5 you fail by - gain 1 exhaustion level
Or something like that...

 

[NeoKobePizza]

I had a similar idea myself for such a system, but using the system shock table in the DMG (page 273).

First off, no Hit Points, damage is measured in "hits".

Anytime you receive damage you will at least take 1 hit.

However, if

a) you're taking your 4th+ hit

or

b) taken damage from an attack= half your theoretical average hit points

you make a DC 15 CON save. If you succeed, you just take another hit, if you fail...

you roll on the system shock table, subtracting the number of hits from the roll.



This hasn't been playtested in the slightest, I just like tinkering with the rules.

 

[Jaldrich6380]

I really like the damage save idea and it's been stuck in my head for a little while now. What I was thinking was using, d20 + Proficiency + CON mod + a Class bonus.

The class bonus would be a +1 modifier gained every few levels depending on class. So fighter types gain 1 every two levels. Rogue cleric types every 3 levels. Mages every 4 or 5. This will help you retain the bounded accuracy concept 5e is trying for.

A level 2 fighter with average CON wearing studded leather would have d20 + d3 + 2 + 0 + 1 for their roll. This seems like a pretty easy calculation as well.
I also thought it might be cool to drop armor from ac and add it as extra dice for a damage save. For example, leather would provide d20 + d2 + mods from above for damage save. Studded leather d3, hide d4.

This would keep the totals in the 0-30 range which is good. You could have the attacker just role damage normally and use that as the dc. May have to scale down some of the damage dice for high cr creatures.

Otherwise I would keep the "always lose one modifier when successfully attacked.
Then when failing by 0-5 take a minor wound. 5-10 miss its medium wound 10-15 critical, 15 and beyond is a mortal wound, bleeding out. I like this in that you don't have to say the first x HP is fatigue. Hits where you make your save are scratches or dings on your armor whereas missing the save its a wound. Much easier to know what to describe. Not sure the status effects for each wound. I like what you have started though above.

 

[GMMichael]

For elegance, I'd keep it to three injury levels, to match the three death saves.

And since the math is a little bulky (average of this, sums of that), the save should be:

Damage save = d20 + (hit die / 2 x level) + (CON mod x level)

versus

DC = 10 + damage result

I pulled the proficiency bonus out since those apply more to skill checks than hit points/damage. Also, the fail-by-X mechanic and increasing-difficulty mechanic are unnecessary.

Didn't notice - did you address healing spells and rests? Those are going to be significantly affected...

 

[Jaldrich6380]

And since the math is a little bulky (average of this, sums of that), the save should be:

Damage save = d20 + (hit die / 2 x level) + (CON mod x level)

To be honest I would say this is is significantly more bulky. A level 10 fighter will have a damage save bonus somewhere in the 50-60 range. This would not be in the spirit of bounded accuracy of 5e where a horde of goblins is still a threat in large numbers to a high level character.

But to each their own. I think the method I suggest achieves bounded accuracy however it would entail scaling down of higher cr creature's damage.

The armor mechanic I'm sort of stealing from burning wheel and if removed from ac would significantly affect the too hit chance but you're wearing plate doesn't make you hard to hit. Just doesn't hurt as much.