Idiomdrottning’s homepage

This is the old version of “Oh, Injury”. The rewrite is here.

Oh, Injury!

We use this rule set in conjuction with Introducing late night fighting; they work on a separate layer and you can use one without using the other, and vice versa.

So many people across multiple forums have helped me work on this, and my own group has helped me so much. The initial idea came from Paul Taliesin.

Good News & Bad News

So the bad news is that monsters no longer need to roll to hit you.

But the good news is that you can make defense rolls to avoid getting hit.

But the bad news is that you can still fail those rolls if you’re unlucky.

But the good news is that attacks now only deal one damage each.

But the bad news is that that one damage comes in the from of lingering injuries, death save failures, or just dying outright.

But the good news is that you have something called Hit Points that you can spend to prevent, block, avoid or negate a hit.

But the bad news is that it can get expensive quickly; for example an arrow from a skeleton’s bow is a 5-damage, meaning it’s a damage that costs 5 hit points to negate. It costs 10 hit points to negate it if you’re vulnerable to piercing, and two to negate it if you’re resistant. And it’s free to negate if you’re immune (talk about discount)! Burning Hands is a 3d6-damage; in other words it costs you 3d6 hit points to negate being burninated.

The even worse news is that in order to make defense rolls you need to say how you’re defending yourself; it doesn’t need to be particularly clever or varied, coud be the same old shield block every time, it just has to fit the situation and how it’s been described.

And the same is true for spending hit points to avoid damage; what you did to get to do a defense roll didn’t work, so what’s your next line of defense? For example alternating parrying with sword and blocking with shield.

Defense rolls

Your defense roll mod is your old AC minus 12 (note it on the sheet instead of the AC), and the DC is the monster’s old to hit bonus +10. so +3 = 13, +7 = 17 etc. Should be fast enough for ya DMs out there.

If you roll a 1, that means that the attack on you was a crit.

Defense rolls are neither ability checks, attack rolls, or saving throws; they’re their own thing. Hobbit luck does not apply. Anything that gives advantage on attacks instead give disadvantage on defense rolls, and vice versa.

Monsters can now inflict harm in the form of…

A wound works the same as a “festering wound” (DMG p 272) with the exception that the “Healer” feat can get rid of non-festering wound, unlike festering wounds. Wounds start counting as festering after one failed check to treat them, or one skipped day of treatment, but that does not reset the count. The only difference that makes is related to that obscure “Healer” feat. An injury roll can still land you a wound that’s festering right away.

Any magical healing, even the lowliest little goodberry, gets rid of all open wounds whether festering or not.

Injury rolls

This is based on the table in the DMG page 272, and see there for details on the entries.

It has the exact same probabilities but is usable even if it’s very clear exactly what part of the body is in danger, and it also lets all the “easily fixable by magical healing” stuff be on an 11+.

For DMs

Flow: Monsters attacking heroes

  1. Describe set up of attack. “The skeleton swings her sword at you like so [show], what do you do?”
  2. Hero describes defense. If they don’t, inflict harm, otherwise:
  3. Say “OK! Please make a defense roll, DC so-and-so-much.”
  4. If they fail, describe the continuation of the attack “the sword glides past your shield” or “the skeleton anticipated your ducking” or similar, “what do you do?”
  5. Hero describes defense. If they don’t, inflict harm, otherwise:
  6. Say “OK! It costs so-and-so-many HP to do that.”
  7. If they can’t pay, inflict harm.

Obv if they make the defense roll, that’s that!

It’s OK if steps c and f become short handed once you’re all very used to the system. This flow is a starting point for you and your group.

Flow: Heroes attacking monsters

  1. Hero describes set up of attack. If they don’t, ask them to be specific (you’re gonna need to know so you can do step c.)
  2. Ask them to make an attack roll vs AC so-and-so much and damage roll.
  3. Say “She spends so-and-so-many HP to” and describe how they defend.

Obv if the attack roll failed, you don’t have to do the “She spends so-and-so-many HP to” part, just describe the defense.

You see how monsters, unlike PCs, don’t have two lines of defense since they don’t have the luxury of getting to make defense rolls. Roll the attack & damage roll in one step.

More Than Just Descriptions

The above flow is then normal back and forth of attacking but what happens when the player makes an inappropriate diegetic move? Let’s go through some of the things that can happen

When they don’t have enough actions to do it

Let’s say Alice says “I step forward and jam my spear into it” when they don’t have enough actions available to trigger an attack roll. That’s your cue to be the Time Master; either negate the attack (“It grabs your spear and turns it aside” or whatever), or say “Just as you’re about to do that”. Then turn the spotlight to another player and ask what they do.

So monsters have three “gates” you need to get through to hurt them: your action econ, their AC or saves, and their HP econ.

When they don’t have enough HP to do it

You’re obv in step g in the monster attack flow so inflict harm!

When they don’t roll well enough to do it

You’re obv in step d in the monster attack flow so describe the escalated situation clearly & ask what they do next.

When they are encrouching on a codified move in the game (that they can do)

Grappling, shoving, disarm, climbing on the enemy etc.

Just go into it. That’s part of the awesomeness of this system. Here’s an example.

“I swing my sword as hard as I ever-lovin’ can, tryna knock it’s sword out of its hand”

This triggers Disarm: monster defends with strexterity instead of AC. I say:

“Roll an attack roll, vs 12 instead of the normal 13.”

When they are encrouching on a codified move in the game (that they can’t do)

Just narrate them failing it.

“I run up on the wall and run along the wall to get to the other goblin”

Running on the wall is reserved for monks level 9 or higher, or “Spider Climb” spell. So if they don’t have either of those effects going, just let them fail. I say:

“You take one step and then you fall prone on your back. The skeleton is over you, and her sword is coming down hard and fast, what do you do?”

When their description triggers another codified move in the game

Just trigger it. Taking a step back is great color but let’s say they go a bit further, and really do try to leave. That triggers OA so I’d say something like:

“When you move that far back, the skeleton can stab at you again without having to fear your sword; his spear is lunging towards you again, what do you do?”

‘Messy’ monster attacks

Now, a normal “non-effect” poison that only deals extra damage does not fall in this category. (For those, it’s just that tough people who are good at making con saves are gonna get a HP discount dodging the poisoned blade, or whatever.)

No, for the ‘messy’ category we are looking at attacks with on-hit effects, such as a crocodile’s grappling bite or a ghoul’s paralyzing claw; how do they work?

Here are some tools so you can carefully emulate those attacks even while using the Oh, Injury! system.


Much milder than an injury roll, you can hand these out like candy. Hope your heroes have magical healing…

Saves as additional costs

Sometimes you don’t just need to spend HP, you also need to make a save.

Here’s an example that put both wounds and saves together:

Ghoul paralyzation

If you fail a defense roll vs a ghoul’s claw attack, and you try to do a second-line defense such as yanking your arm away,

Spend 10 hp and make a DC 10 con save to do that.

If you fail the save, the HP is still spent, you take a wound, and the whole paralyze for 1 min, save ends starts.

“Save ends” means you are trying to shake the effects of the paralyzation and need to roll saves in order to do that.

Action costs

Sometimes you can charge them future actions for some of the moves they are trying to do, and some of these future actions also require successful ability checks.

Frame trapping

There’s actually one more thing that monster’s can inflict, beyond the ones listed above. “Frame trapping”; that means that you, DM, make a note of a HP amount that is added to a cost of a future hero action. You don’t need to tell the players this in the heat of the moment. (They are free to look through this ruleset though. Hi, players!)

There are two types of frame trap points you can inflict [in your notes]. One type is HP loss that they’re definitely are going to have to pay, the other is the equiv of attacks rolls on them: HP loss that they might be able to defend-roll their way out of, depending.

Here’s an example that puts wounds, action costs and frame trapping together:

Crocodile’s grappling bite

If you fail the defense roll against a crocodile biting, the second line defense (yanking the limb away in time) is unusually expensive, it costs:

(The player hears the entire cost before deciding; but if they do decide to try it, they have to spend the 7 hp before rolling.)

If they don’t try, or if they fail, they get a wound because the crocodile is now biting them, having them grappled&restrained and its jaws around their limb.

Trying to strength their way out requires a main action and a DC 12 strength check as normal, but if they didn’t try to yank loose earlier, the DM has noted the frame trap of 7 hp, so that’s what the DM is gonna charge for trying to strength their way loose.

Future rounds, when the crocodile is chewing (all this is going on under water probably, one of my fave CR 1/2 monsters♥), just keep on piling on the wounds & frame trap points.

(You can also charge their ally the 7hp when they try to pry open the jaws to save their friend; that taking it pretty far from the 5e RAW though. Normally you’d charge the grappled hero as they’re tryna carefully move their hand out of those pried-open jaws.)

You can use a similar solution for when the ghouls are gnawing on the poor paralyzed heroes. Just say “OK, you take another wound as the ghoul keeps gnawing on your arm” and then in your own notes, add the frame trap points in. Once they do shake it, they might lose that limb (or die outright) if they can’t pay the HP cost you’re gonna charge.

Inflicting harm

There’s a lot of different kind of harm I can inflict, how can I choose?

I’ll help ya out!

The harm falls into three categories:

Out of action
Death & unconsciousness. Obv be careful with inflicting these unless it’s extremely warranted by the diegesis (they just stand still while a piano falls on their head or whatever).
Only on paper
Death save failures, the true “meat points” of D&D 5e, are scary because you die as you get your third. But in and of themselves they aren’t bad.
Permanent bodily harm
Wounds and injury rolls.

There are also there distinct situations where you are inflicting harm: ‘messy’ monster attacks, when the player can’t afford to defend due to lack of HP, and when the player just don’t defend for some other reason.

Messy attacks

Stick to wounds (and frame traps and the other ‘messy’ attack tools) for this, more than one wound if you need to. The occasional DSF or DSR maaaybe but that’s iffy. The player can’t help that their character got bit by a crocodile! Don’t inflict unconsciousness & injury rolls!

Out of HP

This part of the game is already incredibly codified so shouldn’t requiry any judgment calls from you.

They either die outright if the un-paid-for damage, once they’ve paid all they had, is equal to their HP max, or they’re unconscious & it’s time to start making DSRs.

There’s also the optional rule in the DMG that you have to make an injury roll in some codified circumstances. For options what those circumstances might be, see the DMG p 272. In our group, we have selected to have you roll it when you cross a certain HP threshold.

Weird reasons

Weird & unusual reasons are when you can exert your own judgment! This is when the player describes the hero getting hurt, or when they fail their defense or whatever. Maybe there’s an emotional reason and they don’t want to defend against their own gnome mom, or maybe they can’t figure out a way to defend because of the way the attack is being described, or maybe they haven’t understood this ruleset fully and are used to saying “I get hit” or whatever.

Some guidelines:

Wounds & frame trap is a great start, especially if they are being generous trying to describe the situation realistically, or if they’re being confused. In a safe situation, like it’s a one-and-done trap rather than in a combat situation, if they have plenty of healing magic, you can inflict unconsciousness which they’ll wake up from with a healing word or whatever.

If they’re trying to abuse the system by describing themselves taking light graces in the hopes of getting out of HP costs (which, uh, you’re also frame trapping them so good luck with that), you can inflict injury rolls.

It doesn’t have to be system abuse, it could also be some dramatic reason or other strange reason why they describe themselves taking a sword through the belly or getting their own arm chopped. Just take two DSFs and call me in the morning. Maybe an injury roll + say they’re bleeding so much that it’s a DSR every round.

I mean, be careful with this stuff. Usually wounds & frame trap do the job unless it’s really getting escalated, in which case injury roll and a couple of DSFs is the next step up.