Most RPGs use turn-based combat because it can provide a simple method for clearly resolving the chaotic realities of the battlefield. (Simultaneous action resolution, for example, can work really well with very small numbers of combatants, but then breaks down rapidly as the number of combatants increases.)

Turn-based combat, however, creates mechanical oddities: If you were in a swordfight with someone and they were like, “Hang on a sec. I’m just going to grab a pint and have a quick drink,” you’d just stab their dumb ass. But because we’re using an abstract mechanical structure in which everyone resolves their actions one at a time — even though, in reality, everything is happening simultaneously — suddenly you’re just supposed to stand there watching me take my drink because it’s not your turn.

To deal with this, we add off-turn mechanics that allow characters to react to things that they should, logically, be able to react to, even if it isn’t their turn. In D&D 5^th Edition, these mechanics include the Ready action, reactions, and opportunity attacks.

We can add one more level to this by adding mechanics that allow you to, for example, avoid opportunity attacks. We might want to do this because a character is super-skilled at drinking in the middle of combat, or maybe just because it’s a bad-ass moment. (The Disengage action in D&D 5^th Edition is technically one example of this. In D&D 3^rd Edition you could make Tumbling checks to avoid attacks of opportunity from movement and Concentration checks to avoid provoking while casting a spell.)

D&D 3^rd Edition sought to implement a lot of mechanics from previous editions of the game in ways that were both more consistent and comprehensive. This included inventing the term “attacks of opportunity” and classifying which actions would “provoke an attack of opportunity.” This made sense, but in practice it had a major drawback: It created a huge list that filled nearly two full pages of actions detailing which actions did (and did not) trigger attacks of opportunity, and you either had to reference that list constantly during play or you had to memorize it. Even if most of this list boiled down to common sense, the result was still Byzantine and arcane.

As a result, after 3^rd Edition, there was a practical impulse to avoid this “grand and unwieldy list” of actions. In D&D 5^th Edition, this simplification has been taken to an extreme: An opportunity attack is triggered only when a combatant you can see moves out of your reach, unless they take the Disengage action.

This eliminates the complexity of the list by boiling the mechanic down to a single trigger, but it allows a lot of immersion-breaking shenanigans on the battlefield. And even the implementation of the movement-based trigger is kinda wonky: You can literally run circles around an opponent while firing arrows at someone on the opposite side of the battlefield, but you can’t walk past them while swinging your sword at them. And, bizarrely, this means that creatures with longer reach are actually less effective at attacking people around them.

In my opinion, if you wanted to simplify opportunity attacks, it would be preferable to either (a) eliminate the mechanic entirely (can’t get simpler that that!); or (b) go the other direction.

HARDCORE OPPORTUNITY ATTACKS

By default, any action you take provokes an opportunity attack from any combatant who can reach you.

There are three exceptions:

• Any attack action
• Dodge
• Disengage

In addition, Ready doesn’t provoke, but the action you’re readying may provoke when you take it.

Bonus actions, reactions (other than readied actions), and your free object interaction never provoke opportunity attacks.

Movement provokes opportunity attacks normally.

OPTION: BETTER MOVEMENT OAs

When using this option, movement provokes an opportunity attack whenever a character moves more than 5 ft. within your reach on their turn or moves out of your reach.

Note: Disengage still cancels all movement-based opportunity attacks during your turn. You also don’t provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction.

OPTION: DAMAGE SPELLS

Spellcasters can use their bonus action to avoid the opportunity attack triggered by casting a spell if the spell deals damage.

Note: This rule may be useful to make some 5^th Edition spells work properly. It avoids needing to make all of those spells special case exceptions. Our goal remains One Rule to Rule Them All.

OPTION: HARDCORE RANGED ATTACKS

Using this option, only melee attack actions avoid opportunity attacks. Ranged attacks still provoke.

Note: As with a spellcaster, you might allow a ranged attacker to use their bonus action to negate the opportunity attack.

DESIGN NOTES

Positioning in combat should matter. You want your rogue to pick the lock on the door so you can all escape? Cover their back! You want your spellcaster to rain hellfire down on your foes? Form a defensive line and give them the space they need to do it.

By allowing characters to just do whatever wherever, the 5^th Edition opportunity attack rules cheapen positioning.

Beyond making the battlefield a more interesting space for tactical challenges, I also want things to make sense: If you’re going to do something that isn’t directly focused on fighting, I want you to think to yourself, “Should I really be doing this where the guy with the pointy metal can stab me?”

At the same time, we want to avoid a bunch of Byzantine complexity. We don’t want a big list of what does and does not trigger an opportunity attack: What we want is a simple, straightforward rule that we can easily memorize and apply. We want One Rule to Rule Them All. By flipping things around and listing the very small list of things that DON’T provoke, we achieve that goal.

From a practical point of view, if we end up in a situation where this One Rule to Rule Them All doesn’t make sense, it’s much easier for me as a DM for me to “break” the rules with a ruling that’s more permissive to the PCs than one that isn’t. In other words, saying, “Actually, it would make a lot of sense if this thing you’re doing that would normally provoke doesn’t provoke in this situation,” the players will be much happier accepting that than if I have to say, “Actually, this thing you thought wouldn’t be bad for you is actually going to be bad for you.” A restrictive framing, therefore, can paradoxically give us a greater liberty to make bespoke rulings when and if they’re needed.

ADVANCED DESIGN NOTES

Taking a step back from opportunity attacks, there are two different broad approaches to modeling the idea that you can’t just run willy-nilly around a battlefield or do a crocheting project in the middle of a melee without consequences.

First, you can try to mechanically enforce it: Thou shalt not.

Thou shalt not move past someone threatening you with a melee weapon. Thou shalt not drink a potion if someone has marked you as their target. Thou shalt not run through an area under the effects of suppressive fire.

(My house rules for combat in 1974 D&D, where the procedure effectively makes melee “sticky,” is another approach to this.)

You can also mitigate this approach: Thou shalt not X, unless Y.

For example: “You can move through a threatened space if you succeed on an Acrobatics check.” Or, “If you get hit with an opportunity attack, you have to stop moving.” (If you can avoid the attack, then you can ignore the Thou Shalt Not.)

The other approach is that you can impose a cost for doing it — e.g., “You can do X, but you’ll suffer a penalty.” Or risk getting hit by an extra attack. Or lose an action.

This approach gives more flexibility: If you really want or need to do something, you can still do it. You just have to pay the cost.

And, once again, you can add conditionals that allow characters to mitigate or entirely avoid these costs.

Of course, the highest the cost becomes, the greater your need or desire would need to be to endure it. Conversely, the more negligible the cost becomes, the less influence it will have over the characters’ decisions.

If you think about opportunity attacks within this design paradigm, 5^th Edition’s opportunity attacks are clearly aiming for the second method, and my argument is that they have become so trivial that you would be better off either (a) eliminating them entirely in order to streamline combat and encourage even more movement on the battlefield or (b) using the hardcore opportunity attacks house rules (or something like them) to make them actually matter.

Alternatively, you could abandon that paradigm entirely and maybe try to implement something of the Thou Shalt Not variety.

“If I cast a fireball spell and fill a room with a giant explosion that incinerates a half goblins, shouldn’t the curtain in the room catch on fire? And how did the delicate potion bottles the goblins were carrying all manage to survive the explosion?”

“If I fell into a vat of acid… even if I survive, isn’t there a risk that my boots of elvenkind would be damaged?”

“So if I stabbed him through the chest, which is mithril shirt in perfect condition and ready to be worn into combat?”

Good questions!

Questions like this have been asked since at least the dawn of D&D (and I wouldn’t be shocked if they date back to Arneson’s Blackmoor campaign), so by asking these questions you’re part of a tradition that’s entering its sixth decade!

And, traditionally speaking, there are several broad approaches that have been taken to answering this question:

1. Let’s just ignore that sort of thing. It’s not worth the hassle.
2. The GM can just apply that sort of thing ad hoc when it seems appropriate. (GM intrusions are a great mechanic for handling this!)
3. Whenever we cast a fireball or someone gets hit by a black dragon’s acid attack, we should (a) resolve the attack and then (b) have some sort of procedure for applying (or potentially applying) damage to every single individual piece of equipment carried by the character, tracking the hit points for each individual piece of equipment. It probably makes sense to have a threshold of damage at which the item’s utility is impaired and then another at which it’s totally destroyed. Oh! We’ll also need repair rules, so that damaged equipment can be recovered before it’s lost forever!

The great thing is that anyone actually doing #3 inevitably discovers that it’s a huge pain in the ass and they rapidly circle back to #1. So it turns out there’s really only one solution, it’s just a question of how long it takes for you to reach it!

… but there are a couple things to think about.

First, it turns out that “you can cast fireball or meteor swarm and unleash overwhelming hellfire upon your enemies, but if you do that you risk losing all the kewl lootz they’re carrying” was actually an interesting balancing mechanic that varied gameplay and created interesting strategic choices.

Second, the verisimilitude of “your acid arrow melts a hole through the goblin’s chain armor!” or “as the flames of fireball clear, you can see that all the books in the library are aflame!” is appealing. It just makes sense! That’s why, after five decades, we’re still asking these questions!

Plus, it can really make the wizard’s player feel like a badass.

Is there a way we can have the best of both worlds?

Maybe.

LOOT DAMAGE!

When looting an NPC’s corpse, roll 1d6 for each:

• Armor
• Weapon
• Magic Item (or other significant item)
• Container (e.g., a backpack)

On a roll of 1, the item was damaged. (Their armor is rent; their blade broken; the potion bottle shattered.) If a container is indicated, the container is ruined and you should additionally make a check for each item bundle in that container.

Non-Fragile Magic Items have advantage on this check. (Roll 2d6, and both dice must roll 1 for the item to be destroyed.)

Fragile Items or items that are particularly vulnerable to the attack(s) suffered (e.g., paper blasted by a fireball) have disadvantage on this check. (Roll 2d6, and a 1 on either die means the item has been destroyed.)

Area Effects, like a fireball or dragon’s acid breath, trigger a check for all unattended loot in the room / area of effect. You can wait until the PCs start looting to make these checks, but a check is made for each area damage effect! (If there are valuables about, use with caution!)

DESIGN NOTES

The advantage of a loot-focused approach is that the bookkeeping is pushed to the point where the party is, in fact, looting the bodies. Listing, distributing, and recording loot is, of course, already a moment in the session that’s focused on bookkeeping. So rather than bogging down the action-focused combat sequences, this system.

By using a simple binary check (destroyed or not destroyed?), we’re also simplifying the mechanic so that it can be resolved quickly and efficiently. Simply grab a fistful of d6s, roll them all at once, and check the condition of each item as you list it for the players.

You can easily tweak this procedure by varying the dice size until you’ve got a frequency of loot damage that feels right to you.

GRITTY VARIANT: PC EQUIPMENT

In addition to checking for loot damage, when a PC is slain or brough to death’s door, make a damage check for their equipment (as per the loot check).

These checks might be triggered only if a PC is actually killed. (“We were able to raise you from the dead, Norgara, but not your plate armor.”) Alternative thresholds might vary depending on what edition of D&D you’re playing, and in some cases you might have multiple triggering events:

• D&D 5^th Edition: When the PC has to start making death saves.
• D&D 3^rd Edition: The PC has negative hit points, even if they haven’t reach their death threshold.
• D&D 3^rd Edition: The PC suffers massive damage.
• AD&D: The PC is reduced to 1/10^th their maximum hit points.

For a truly brutal variant in any edition, you could also trigger an equipment damage check any time the character fails a saving throw against an area effect. (Or, for a less painful version, when they roll a natural 1 on a saving throw.)

DESIGN NOTES

In D&D 5^th Edition, in particular, triggering an equipment damage check on death saves gives them an extra bite. You REALLY don’t want to be popping up and down on the battlefield! Get some healing to your allies!

INCIDENTAL DAMGE

Incidental environmental effects and damage — e.g., curtains being set on fire, windows being blown out, spilled oil being set aflame — is still be handled by via GM fiat and the whim of description.

If you want a rudimentary procedural generator for this, however, you could roll an additional 1d6 for each area effect and, on a roll of 1, make a point of including a significant environmental effect (e.g., the dragon’s acid breath melts the floor, creating difficult terrain; or the fireball spell causes the barrels of oil in the room to explode).

ADDITIONAL READING
Shields Shall Be Splintered!
5E Encumbrance by Stone

Disclaimer: I am not entirely sure how serious I am about this.

DISCUSSING
In the Shadow of the Spire – Session 38D: Arrows & Skulls

The room beyond was filled with carefully arranged piles of bulky, broken machinery bearing the unmistakable patina of age. Kneeling amidst this equipment – her back to the door – was a single ratling dressed in pale yellow robes.

“Not now! I don’t want to be disturbed!” she hissed.

Tee put an arrow through the back of her skull.

“… was that Silion?” Tee looked back at the others. “I think that was Silion!”

If you’ve been hanging around the Alexandrian for a while, this is a moment you may recognize. I’ve talked about it in articles, videos, and So You Want To Be a Game Master, among other places. When I talk about not fudging your dice rolls, this is a moment I’m thinking about.

Because Silion is a big deal. I believe the PCs first became aware of her in Session 9, which means the players have literally been hunting her for years. And we just introduced a new PC whose backstory and primary campaign hook were linked to her!

So if we were going to prep plots or enforce preconceived outcomes or try to “preserve” the dramatic moment, this would be THE MOMENT to do it, right? Silion can’t die like this! A single critical hit to the back of her head? The PCs never even saw her face! This is a disaster!

… except, of course, it wasn’t.

It’s been just over fifteen years since this moment happened at the game table, and my players still talk about it. They’ll probably be talking about it until the day they die. It’s a cherished memory from the game table.

Okay, but… why?

The Principles of RPG Villainy breaks this down in more detail, but the short version is that, for the players, this was not anticlimactic in any way. It was a huge reward for all their hard work: They had, in fact, worked for years to get here. They’d come up with clever plans to infiltrate the temple (even if not all of them had worked). They’d successfully snuck their way down to this inner sanctum.

They earned this.

And that’s why, a few minutes later, they can gleefully taunt Silion’s mate, Urnest, with what they’ve done. Because they were the ones who did it.

If I had fudged the results — maybe by boosting her hit points or bumping up her AC so that they couldn’t confirm the critical hit — that would have been a huge letdown for the players. Sure, they would have gotten to face off against Silion and maybe she’d summon reinforcements and there’d be an epic battle and the PCs would triumph or whatever… but none of that would have been something they actually did. It would have just been a thing that happened to them.

And the really key insight is that, conversely, if I’d tried to pre-script and force this moment — surprising Silion and shooting her in the back of the head! — it would have also fallen flat. Because it still wouldn’t have been something that the players actually did.

This is why moments like this — moments of great truth at the table — are so important. Because they’ll teach your players that what’s happening in the game is really happening. It’s not a script. It’s not a trick. If they achieve great victories, it’s because they actually earned those victories. And if they suffer horrible defeats, that’s a burden they have to bear… because they know it could have gone a different way if they’d made different choices.

As the players learn that lesson — as the belief of it seeps down into their souls — it will literally breathe life into every other moment of your campaign. It will elevate everything you and your players do to a new level.

When you truly play to find out — when you actively play scenarios instead of prepping plots — you’ll discover that moments like this aren’t unusual. What makes this particular moment notable, perhaps, is that it simply might be the purest example possible:

Boom.

Arrow to the head.

Campaign Journal: Session 39A – Running the Campaign: Using Scenery & Traps
In the Shadow of the Spire: Index

DISCUSSING
In the Shadow of the Spire – Session 38C: Scouting the Temple

Nasira quickly muttered an incantive prayer and projected a sense of clairaudience into the sanctuary hall below. She was in time to hear the ratmen deciding to summon reinforcements. She quickly informed Tee of what was happening, and Tee rushed back to the street in case the ratmen headed that way (in which case she could follow them).

But she saw nothing: The ratmen didn’t leave through the front door. Instead, Nasira heard the sound of scraping stone…

When I ‘m prepping published dungeons, I have a tendency to make them BIGGER.

Sometimes I think this might be a bad habit, but the results in actual play seem to be good.

What’s really going on is a couple of things: First, when I’m planning a campaign, I’m often pulling stuff in from a bunch of different sources. Sometimes that’s two different adventures that get linked to each other using node-based design, but sometimes I have two different “ruins of a dwarven city” adventures… and couldn’t they be the same dwarven city? I can just make one of the adventures Level 1 of the dungeon and the other adventure Level 2, and now, instead of two small dungeon cities, I have one BIG dungeon city that truly lives up to the name. Plus I can mix all the scenario hooks from both adventures and create all sorts of dynamic vectors for the PCs!

(See The Campaign Stitch for a deeper dive into this sort of thing.)

The second thing that happens is that I simply get inspired. As I’m reading through an adventure, all of the adventure’s cool ideas will start sparking off new cool ideas in my own brain: Sometimes those are ideas I can just add to the existing room key, but in other cases it’ll make more sense to pile ‘em all up and fill a new sub-level with them.

The Temple of the Rat God is a good example of what this looks like in actual practice.

This adventure exists because the Nights of Dissolution mini-campaign, which was one of the building blocks for In the Shadow of the Spire, features several of the chaos cults in Ptolus working with each other. And I basically thought, “Why not all of them?” So I went through the Ptolus and Chaositech sourcebooks and started grabbing chaos cults. Then I made a few of my own. Then I started linking them together with clues, creating a node-based campaign structure.

The Temple of the Rat God comes from the Ptolus sourcebook (p. 394), where it looks like this:

As you can see, it’s not fully keyed. So I took the map, made some modifications, and keyed it:

You can see I’ve added additional hallways leading off the edges of this map and connecting to other maps.

Elsewhere in Ptolus there’s a Ratman Nest (p. 442). This is a fully keyed adventure designed for the DM to drop it pretty much anywhere in the city sewers where the PCs might be chasing ratmen:

I decided to put it here, once again with some minor modifications. (You can see the changes on the map above, including the addition of a sinkhole and the connection to the temple.)

During my campaign prep, I’d also thumbed through my monster books for inspiration. Knowing that ratlings and the Temple of the Rat God were on the menu, I scooped up cranium rats from the 3^rd Edition Fiend Folio and the rylkar (dangerous fire rats) from Monster Manual V. (I also linked the latter to ash rats from Monster Manual II.) I rekeyed the Ratman Nest map to include cranium rat nests, and then added a whole new level down the sinkhole — the Rylkar Depths:

The result is a fairly expansive example (showcasing, as it does, a wide gamut of techniques all coming together), but it’s what I enjoy about working with published adventures: When the creativity of the author and the creativity of the game master combine, you end up with richer and more varied material than you could have achieved on your own.

I’m a really big believer in the power of collaborative creation, whatever form it might take.

This is a topic we’ll also likely revisit as the PCs begin delving deeper into the Banewarrens. There, too, I took inspiration from the core concept of the adventure and then drew on a wide variety of sources to create fresh wards: What else could the Banelord have locked away down there?

Campaign Journal: Session 38D – Running the Campaign: The Secret Life of Silion
In the Shadow of the Spire: Index