The Devil’s Bargain: Blades in the Dark Success with A Cost in D&D 5e

Can we go ahead and agree that it is patently not fun having a great plan that all falls apart just because the dice turned against you? Like, you’ve planned the perfect assault on the evil baron’s castle. You’ve done a bunch of legwork, casting spells and infiltrating the keep to gather information. You’ve greased some palms, flipped an agent who will open a seldom used postern, and stolen the guard’s patrol schedule. Everything is set to go and lift the McGuffin from the treasure vault, but when it comes time to actually execute the plan, you can’t roll above a three. Your ranger can’t stealth, your warlock misses the arcane wards which shock him into unconsciousness, the barbarian can’t bend those bars, and the rogue breaks three picks trying to get that puzzle lock open. So instead of a smooth infiltration and the reassuring weight of a plot coupon, you’ve got a comedy of errors and the sound of a hopeless amount of booted feet pounding down the hall, hot on your heels.

Now, failure is dramatic. When the chips are down, that’s where hero stripes are earned. The Ragtag Bunch of Misfits somehow snatching victory from the jaws of defeat is a trope for a reason. We love those stories. With that firmly in mind, remember that sometimes success with an added cost can be just as dramatic. Presented for you approval, enter through the trapdoor amidst sulfurous smoke, The Devil’s Bargain.

Take a closer walk with me.

This is a mechanic that I’ve blatantly stolen from one of the coolest RPGs I haven’t yet had the chance to play, John Harper’s “Blades in the Dark”. Being an unrepentant fan of skullduggery and a good heist, something about the whole system sings for me, but what I particularly love is the risk/reward mechanic of getting extra dice to roll at the cost of harm, higher stakes, or later unavoidable trouble. This is the Devil’s Bargain. While a common footpad might not be able to spring that puzzle-lock, one of the ne’erdowells of “Blades in the Dark” might press their luck, accept a Devil’s Bargain from their Game Master and click that last tumbler into place…triggering the alarm. Now they’ve overcome the problem, but they’ve traded it for another one.

Dramatic, no?

Now Dungeons and Dragons doesn’t have a mechanical basis for the kind of edge that accepting “bad stuff ™” might narratively grant. When I first started brainstorming how it might make the jump from system to system, I was thinking that it might be a way to get an after-the-fact Advantage d20 on the roll, but I think that’s kludgy and harmful to the fiction that we’re building when we roll the dice. By which, I mean, that it seems like it’d be ripe for abuse and easy to turn into a big ol’ cheese sandwich. It would, of course, also be thwarted any time the character already has advantage, as most characters will typically look for every source of advantage for the kinds of pivotal rolls that best serve the Devil’s Bargain. So what to do?

In Blades in the Dark, anyone can offer a Devil’s Bargain before a roll is made. This supports the more collaborative and conversational fiction-building of the system, but I think it affords a little too much tactical exploitation in a system so crunch-bound as Dungeons and Dragons. Game Masters have final say in Blades in the Dark, curating which ones are valid and which ones are too punishing, not punishing enough, or not building the story in a satisfying direction. I think that could work in a group that has been playing together for a long while and is comfortable with that sort of narrative meddling, but I think the general usage case should fall squarely upon the shoulders of the DM. And I think that judicious use by a DM who is attempting to create good drama and serve the narrative justifies how I believe the Devil’s Bargain should be used in 5th Edition Dungeons and Dragons.

Prepare the pitchforks.

“He’s messing with the rules again!”

I think that, when a character rolls a failure on a check or save that has dramatic and narrative weight, the DM should have the option to play the role of Mephistopheles. “A seven does not succeed as you rattle the tumblers of the puzzle-lock. However, I have a Devil’s Bargain for you. Killian thinks that with a good solid wrench, he can force the lock, revealing the treasure within. But he will trigger the alarm. What do you do?” See? It’s a narrative high-point where everyone is biting their nails. It’s dramatic to fail here…but it’s also dramatic to succeed with a cost, isn’t it? What is the character going to do? You’ve given them something to chew on. Don’t let them. Make them choose quickly. They will succeed. But…

Understand that I believe that failure is an integral part of Dungeons and Dragons, and every other roleplaying game. I think that it’s important to storytelling. I am not suggesting the Devil’s Bargain as a common occurrence, or as an alternative to fudging rolls or manipulating DCs or any of the other shenanigans that DMs get up to. I’m certainly not saying that the idea of porting over this mechanic is not every bit as polarizing as those self-same shenanigans. I’m only suggesting it as a way to further the drama, the tension and release that is the juice of this game. In that way, I think the Devil’s Bargain might just be the thing to push the narrative in interesting ways, and to give the players some control over what they’re willing to endure to see their well-laid plans succeed in spite of the dice.

The ranger manages to muffle his gear as he sneaks through the barracks, but has to proceed barefoot. The Warlock’s patron whispers a warning before he touches the active glyph of warding, but demands a terrible price. The barbarian twists the bars and clears the path for his friends, but cannot pass through himself. The rogue disables the lock and gets the goods, but the entire castle is now aware that there are thieves in the house. Now barefoot, beholden, separated, and sought after, our ragtag bunch of misfits get to snatch victory from the jaws of defeat. All according to plan.


Somewhere, there’s a Devil laughing. It might just be you.


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2 Responses

  1. Erik says:

    I do something pretty similar to this in my Pathfinder 1 campaign, but it came out of trying to hack-in Dungeon World’s partial success mechanics, and gets triggered by rolling a near miss. We call it over-committing – when they roll within five of the target (including combat rolls), I give them the option to immediately succeed but they have to narrate how the success came with a cost or put them in a bind.

    • Drake says:

      Failing forward and success with a cost are things that I absolutely have carried with me into every game I play. There are variant rules for it in the PHB, but they’re very “this is possible, mechanize as you like.” My 5e-based game that I’m hacking together is absolutely going to have rules for it.

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