Reaction Rolls: Why 5e DMs Should Use this Old School Rule

Last Updated on October 25, 2023

I’ve been playing a lot of BX D&D lately — which stands for Basic/Expert, the version of the game that was being played around the beginning of the 1980s. 

There are a whole heap of articles I could write on why that’s the case, not to mention the differences between old school roleplaying and 5e, but I think I want to hold off on a “why you should try old-school gaming” article for now. 

What I do want to talk to you about are Reaction Rolls — a rule found in past editions of D&D that got cut from the rules somewhere between the mid-80s and today — and why 5e dungeon masters should consider reintroducing this rule to modern play. 

What’s a Reaction Roll? 

Reaction Rolls are a rule that covers what happens when the players’ characters encounter a potentially hostile monster or group of NPCs.

When the two groups bump into each other, the Dungeon Master (referred to as the Referee in the old days) rolled 2d6 and added up the total. 

(The Referee part is something I want to come back to in a minute.)

The result of the Reaction Roll could also be modified by things like a player character’s Charisma modifier, a bribe paid by the adventurers, the fact they’d done something to intimidate the creatures, and so on.

Each tangible thing done usually added a +1 bonus, unless the Referee ruled otherwise. 

(Obviously, the PCs’ behavior, appearance, Charisma, and reputations could also decrease their reaction roll results, which is why the players in my bi-weekly game always pony up for a bar of soap whenever they visit the general store.) 

Once the 2d6 had been rolled and the penalties/bonuses were applied, the Referee compared the result to a table with higher outcomes meaning that the monsters would be more inclined to be friendly to the adventurers and lower outcomes usually resulting in combat. 

BX D&D contained the following table. 

There have been more and less complex iterations of the reaction table over the years, but the essence has always been that higher results meant friendlier monsters and low results usually meant a fight was about to break out. 

Now, not every situation called for a Reaction Roll.

Obviously hostile monsters (especially ones not “intelligent enough to avoid an obviously superior force,” according to the Holmes edition of Basic D&D) might just attack immediately, no roll required.

A murderous owlbear hungry for supple, juicy humanoid flesh isn’t going to need the DM to make a roll; it’s obviously going to charge the party and tear the wizard’s face off. 

Likewise, a gaggle of friendly halflings meeting a party of well-known, high-level adventurers for the first time aren’t about to drop to all fours and try to tear the wizard’s face off.

Well, they might. It depends if you’re playing Dark Sun or not. Halflings are rowdy in that setting. 

However, in those uncertain moments, when time seems to stand still and everyone is waiting with bated breath to see what everyone else does next…

When you’re waiting to see whether the orc wearing a necklace of halfling skulls (or the halfling wearing a necklace made of orc skulls, which is way scarier) is about to invite you to his house for dinner or invite you to his house for dinner… That’s when reaction rolls are my favorite thing in the world. 

Why Use Reaction Rolls?  

So, right now you’re in one of two camps.

Either you read this and thought, “Hey, that sounds really cool. I’m going to try it!” or you just opened your big mouth made of straw and said, “You mean the monsters don’t just do what I tell them to do? How am I supposed to prep for that?!”

And you’re right, strawman, randomly rolling a 13 on a reaction roll might mean that your party suddenly has a bunch of kobold friends that you need to come up with names and voices for. That can happen. 

But that sort of thing is part of why I’ve been playing BX D&D recently and not so much 5e. I think old and new editions of the game are both great at different things.

Modern D&D (whether we’re talking about 3.5e, 4e, or 5e) is very, very good at heroism, powerful characters, and sweeping narrative moments carried off by great big lovely setpieces.

One of the things that old-school D&D is very good at is all the moments in between – poking at cursed statues and trying to get rich before you get killed. It’s also great at helping me feel like I’m not a jester dancing for my players’ amusement. 

5e (not just 5e, this has very much been the mode of Dungeons & Dragons since 2nd Edition in the 1990s) presents the role of the Dungeon Master in a way that feels all-powerful, like an author or curator of the players’ experience.

Adventures — even the more sandboxy ones — are all about getting you from one big set piece to another. Random encounters are, tragically, a speedbump.

Sure, unexpected things can happen, but they always feel like they’re the result of the players subverting the DM’s grand plan (or the prewritten module) — taking the game off the rails.

And then, when things go “wrong,” it’s the DM’s job to get them back on track, so to speak. 

In a game that’s all about randomness (where I literally have never met a player or a DM who doesn’t love rolling on the wild magic surge table), I find this kind of weird — stifling even. 

Now, I’m not saying that old-school D&D doesn’t have rails. It does. It has plenty

However, I think rules like Reaction Rolls help remove the paradox that is the role of the modern DM: someone who has to respect the players’ agency and imbue their choices with meaning while at the same time getting the story from point A to B to C in time for the big boss battle at point (Dragon)

Stuff like Reaction Rolls take the pressure off. They’re an implicit signal from the game and its designers to the DM that they don’t have to know exactly what’s coming.

Sometimes, they can sit back alongside the players and enjoy the ride while the game just does what it does. The journey is the destination, etc. 

(Remember when I said I wanted to talk about the role of Referee versus Dungeon Master? This is it. Words have meaning, and just as Dungeon Master implies omnipotence, omniscience, and a thinly veiled allusion to godhood, Referee is a far more neutral term). 

I love reaction rolls for the same reasons I love Random Encounters. They make the world feel alive, and they make it feel alive to me as much as to my players. 

Hive of the Eye
© Wizards of the Coast by DiTerlizzi

How Do I Use Reaction Rolls in DnD 5e? 

So, if I have piqued your interest, let’s talk about how to use Reaction Rolls in D&D 5e

First — and this is something I do in BX as well — have your players do the roll or, if you want to do it, do the roll out in the open.

It’s fun, it’s exciting — I’ve never not had players enjoy it — and it reminds your group that, for this one little moment, you’re as much a player as they are.

Sometimes I’ll do this in secret if the monster is particularly crafty and able to hide its true intentions, but most times I’ll roll those bones out in front of the gods and everyone. 

Next, let’s talk modifiers.

I think that there needs to be a blanket ban on applying Proficiency Bonuses to Reaction Rolls — along with other abilities like the bard’s Jack of All Trades or the Rogue’s Expertise. That stuff throws off the numbers too much. 

You can add your Charisma bonus to the roll. However, to do so, you need to pass a DC 10 Charisma check. 

Just like in BX, if the players do something especially cool or clever, like making a rousing speech, bribing a guard, flirting with a dragon, etc., they can get a +1 bonus per tangible thing.

Their reputations, appearance, race — you name it — could get them a bonus or a penalty here depending on the situation (maybe the dragon really likes eating elves). 

Then, roll and apply modifiers. I’ve tweaked the BX table a bit to reflect the higher modifiers you tend to get in 5e

Now, the beauty of Reaction Rolls is that you don’t just have to use them in combat, and you don’t have to stick to the prescribed entries here or anywhere else. 

When in doubt, roll 2d6, and add some numbers. If it’s high, the monster/NPC is probably going to be friendly (within reason).

If you roll low, they probably want to act contrary to the PCs’ interests — whether that means outright attacking them or just undermining them when it suits them is up to you. 

Next time I think I might build on the idea of using reaction rolls as a way to help generate NPCs on the fly.

For now though, I urge you to try rolling 2d6 the next time your 5e players bumble into a random encounter or a new NPC’s house.

I think you might like loosening your grip on the reins for a minute and seeing where the dice take you. 

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