D&D 5e

Unearthed Arcana: Mass Combat Breakdown

If I had had to guess what we’d see in this week’s UA, I don’t think a new round of mass combat rules would have made the top 5, though probably the top 10. Not that you asked, but: the #1 spot easily would have gone to the mystic, followed by downtime rules that might have a hint of domain rulership flavor, followed by races or rules for some non-FR setting, then maybe another ranger iteration, and finally a warlord class or subclass (above and beyond the banneret from SCAG). These rules are a second iteration of an early UA article that is damn close to its second birthday.

I’ll be talking about comparative cases with the first mass combat document as much as possible, because if you’ve read any of the History of the Classes series, you know that design trends are as interesting as outcomes. The number-one-with-a-bullet change here is scale. We’ve shifted from a base of 20 combatants forming a unit to a base of 400. So, you know, that will probably have some impact. I criticized the first document fairly heavily for covering only large-skirmish-scale warfare, with no realistic ability to work with Pelennor Fields-level armies. Units of 400 may still be burdensome if you’re hoping to recreate historical or fictional battles, but it is a damn sight closer. Naturally, it’s still critical for D&D to support individual heroics, which – along with an innovative action economy – was a major strength of the first set of mass combat rules; let’s see what happens here.

This system cares about two core statistics: battle rating and morale rating. Battle rating is a conversion of the CR of all creatures in a unit; in this way a single high-value creature could hugely skew the BR of a unit. We may not be in the habit of calculating a PC’s CR, so it’s lucky for us that this document doesn’t do that. Character-scale combat comes at the end of the document, though. Anyway, there’s something a bit brain-breaking about having CR 20 creatures that don’t resolve as individual characters, in anything short of just staging the major engagements of the Blood War (where units of 400 are probably woefully insufficient). Creatures above CR 20 presumably are treated as individuals – but you could also just project the 1 CR = +4 BR pattern upward and call it a day.

Anyway, that 400 number I keep tossing around is space filled by Medium or smaller units; larger units take up more space, and thus you can fit fewer of them into a single unit. This prioritizes CR by density – that is, a Medium or smaller creature’s CR is more valuable than a larger creature’s CR. A unit of ogres (400/4, so BR 100) is in bad trouble against a unit of berserkers (400/1, so BR 400). For what it’s worth, the entries for ogres and berserkers both call out that they form units like I’ve just described. On the other hand, if you have 400 ogres divided into four units and 400 berserkers in one unit, the ogres have a huge lead on the action economy, right? Yes, but it will never, ever matter, because d20+100 never beats d20+400, so the ogres lose… not quite instantly, but they certainly don’t land a hit. In individual combat, this goes quite differently. Poking at the math a bit more, there aren’t many viable use cases.

Moving on, each unit has a commander, and that commander’s Cha modifier factors into morale rolls. The commander belongs to the unit but does not count toward determining its size.

The mounts of mounted units add their CR to the battle rating, but I’m not clear on how they factor into the 400-count limit. If the rules treat a warhorse as the Large creature that it is, then the CR ½ horse is a huge impediment to the unit strength of the CR 3 knight, using up 5 Medium-creature spaces to add 3.5 total CR.

Morale rating is a value between -10 and +10, determined by DM fiat and guided by the positive or negative influence of a series of factors. The Factors Affecting Morale list is solid, lacking only “recent defeat or victory,” except insofar as that’s a judgment of “incompetent or ill-prepared commanders.”

Battles operate on a scale of minutes rather than 6-second rounds, which is the right decision for the use case, and also a throwback to the round times of 2e and earlier, which were themselves holdovers from D&D’s wargaming roots. Movement gets rescaled to that amount of time, which is good, since the size of a unit – a square 100 feet on a side – is otherwise so large that a unit with a speed of 30 ft would still overlap with its starting space, even when Dashing. The big problem with multiplying speed to the minute-round scale is that a unit’s move brings it from outside a longbow’s max range to melee contact in a single move, so ranged weapons don’t accomplish much.

The initiative calculation is a fixed rank, not a roll. Many people all around the internet have noted that the commander’s Cha modifier factors twice in initiative, since it’s 10 + unit morale (which includes the Cha mod) + the commander’s Cha mod. Until further notice, I’ll assume this is an error and not an attempt to increase the impact of a high Cha, but it’s only initiative and doesn’t affect play nearly as much as you might think. The initiative rules note that the action economy behaves like normal, and units can move-attack-move like normal, but the rules on movement two paragraphs down and the difficulty of wiping out an enemy unit mean that we’re really just talking about ranged units doing this. Specifically, you must use the Disengage action and pass a morale check to leave adjacent contact with an enemy unit.

The Action Options are pretty straightforward, other than the piece I just mentioned about Disengage. The Attacks section, for how to resolve the contested BR roll, is another real problem. Let’s be real, 1d20 + a large number vs 1d20 + another large but not identical number is almost always going to be so far outside the spread of 1d20 that the Tie and Attacker Wins by 10 or Less outcomes can be safely ignored. Even if they couldn’t, a win by 10 or less degrading BR by 2 can be all but ignored when BRs scale in three or even four digits. When the defender wins the roll, nothing happens; when the attacker wins by 11 or more, the defender loses 5 BR (still trivial) and has to roll a morale check (the only actual danger here). For no apparent reason, a unit automatically escapes when its morale breaks. There are also ways to get advantage or disadvantage on each side of this contested roll, but as I’ve just explained, this won’t ever matter.

The rules for morale checks are fine, except that it could take hours of attrition to grind a unit down to half its starting BR, even when it loses every roll by 11 or more.

Next up is the rules for characters in mass combat, which boil down to “ignore everything that came before, zoom in, and resolve a few rounds of personal-scale combat.” This tries to provide for PC spellcasters to toss off spells that would matter in mass combat, like fireball or wall of ice, but it shines a harsh light on the contrast of effectiveness between personal and mass combat. All the worse, in fact, for spells with a duration.

There are a few DM hints about how to run a mass combat in a satisfying way, keeping the focus on the PCs and letting them face interesting named NPCs.

Whew. What can I say about this document? This is the first unmitigated failure that UA has released. All of my UA analyses necessarily point out negative things, but in general I think Mearls and Crawford do strong, compelling work. I don’t know what happened here, and from my own experience as a professional game designer, I know better than to speculate. Let me leave it at this: any two units that are not the same size and CR are all but guaranteed to be 20+ points apart in BR, and once that happens, there’s no game. The things that give a force a superior BR don’t follow from the fiction.

We’ve seen UA iterate a piece of rules through multiple steps before. It can be an erratic path, as it seems that the designers prefer to scrap the whole of the previous document and start fresh in many cases. I think we’ll see at least one more iteration before mass combat rules go official, and I expect that they’ll be phenomenal. Maybe they’ll do me a favor and come out right around when I’m working on a History of Mass Combat Rules series? A columnist can dream.

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  • I’m sure there are groups that want to command and fight against these units, but I haven’t played with them yet.

    • Given the VERY long history of mass combat rules in D&D, to say nothing of other heroic-adventure roleplaying games, I’m gonna say there’s strong evidence that people want this kind of content. In particular, history and fiction like to lionize field commanders and generals, creating the desire to inhabit that role. I mean, if a game hands you the chance to play Marcus Agrippa, you damn well play Marcus Agrippa.

      (I may be totally obsessed with Roman and Byzantine history. Don’t judge me, this is who I am now.)

    • I’m sure you are right and I was excited when they announced the first version was coming post DMG. I am one of those people who want to run this type of content.

      The battle in Germany in Gladiator and LOTR’s Pelennor Fields are great examples I would want to run.

  • MTi

    In the previous-but-not-yet-finished campaign I’m playing we’re supposed to lead one final battle royale that is to dictate the fate of Faerun. So this UA comes in handy so we can playtest these rules.

    We do not know yet when this is to happen yet, as our current campaign runs strong and one of my fellow PCs is currently super-busy with his professional projects, but rest assured that when we are to do this you’ll know how it went. At least I hope it’s going to happen soon enough.

    • I would strongly encourage your DM to take excruciating care in building and balancing the units. A naturalistic approach is very likely to create an auto-win outcome for one side or the other.

  • Marandahir

    I like the morale-BR grind element of these rules. I do think that the size and speed and accuracy issues are damning to this particular iteration, but the basis of assigning a Unit-wide HP-like value that represents the survival of that unit in battle is a very useful abstraction. And the morale modification is smart and thematic. I want them to refine the math to make it more streamlined and yet also account for the size/speed/accuracy problems. Bounded Accuracy should be a universal value. If a multitude of peasants can take down a Balor – given enough units to keep fighting – that should have an impact in mass combat rules. The big issue here seems to be that it’s trying to align all units by size rather than by CR. 400 Berserkers should indeed be much stronger than 400 Ogres, because they share a CR, and yet 4 Berserkers can fill the space of an Ogre. But that shouldn’t mean that the Ogres can’t hit the Berserkers at all. It should mean the Berserkers should drive down the BR of the Ogres faster than the vice-versa.

    I’m really missing the victory points from the earlier iteration, though I understand that some people might find these as artificially stringent on a DM’s ideas for a combat. Rather than a set number of challenges for the army and the party to achieve before they win the battle, I think guidelines for developing adventure goals and mapping out the progress of the battle, possibly using victory points as an optional tool to help manage that.

    • I didn’t phrase things in terms of bounded accuracy in the article, but yes, this is 100% a bounded accuracy issue. I don’t have any problem with treating a whole unit as a single entity for offensive and defensive purposes, but going down to a single number isn’t working for them.

      My core issues with the morale-BR grind are:

      1. Getting a high-morale unit into can’t-fail territory isn’t that hard, which means there’s technically no way to eliminate them – the text mentions that units can fight even into negative BR.
      2. Units breaking and then regrouping (following a stirring speech) are a major element of mass combat, and dumping that cuts out a great way for PCs to be heroic.

      Why should 400 berserkers be stronger than 400 ogres, if they’re the same CR? To me, that’s an outcome you’d specifically want to prevent.

      Units that stay in formation don’t run at a full tilt (other than cavalry in a charge), that’s for sure, so multiplying speed by 10 just because the base unit of time increased ten-fold isn’t a necessary outcome. I get that they’re working really hard to keep things simple, but when simplicity breaks things (like weapon ranges), do something else.

      Victory points are a great idea on the level of encounter design, but this document makes only a handwave in the direction of encounter design – it’s much more concerned with two armies beating each other to death.

  • crimfan

    I missed the BR calculation when I read the document and slid right past the fact that they add! It’s pretty clear they haven’t thought through the diminishing returns aspect of increasingly larger units. Offensive power does not increase linearly per additional unit of force, though larger units can take a bigger beating.

    I’m surprised they haven’t seen or been told about Lanchester’s Laws, which could be translated into game rules, I bet: https://en.wikipedia.org/wiki/Lanchester%27s_laws

    • To be honest, I think the majority of reactions I’ve seen online divide into “checked the math” and “didn’t check the math,” lining up almost 1:1 with whether or not they liked the rules. But then, if everyone checked the math, they wouldn’t need my article! 😉

      In all seriousness, I often don’t run the numbers in any depth; it just happens that this time, I wanted to try one simple test case, picked two likely opponents out of thin air, and found what I think are serious problems. I’ve seen a lot of other people (for example, in an ENWorld thread) do the same, often facing counter-arguments that there should never be that many (creature type) gathered together. If you don’t accept that there could be 400 veterans forming a unit, I’m not sure what you think “veteran” signifies.

      Lanchester’s Laws are interesting, particularly where they fail to predict a battle’s outcome. =)

    • crimfan

      Well the whole point of a model is often to allow you to figure out if you can beat it. 😉 That’s where superior tactics or, of course, Napoleon’s favorite attribute in a general, luck.

      What I think Lanchester’s law would give here is a way to determine the scaling and diminishing returns aspects.

      Also, melee versus missile units aren’t factored in hardly at all. Melee units should generally be linear in the Lanchester sense, while missile units are square, and indeed they probably won’t even be linear because only the edges of the formation can attack. The rest are just part of the mass. This means that missile units meeting melee units should, assuming they can keep distance, do some seriously bad things.

      If you’ve ever read the well-researched Sharpe books, or indeed anything else by Bernard Cornwell, the massive advantage that infantry line formation has over infantry column was evident, but line is highly vulnerable to fast moving threats like horsemen.

      Other things the rules don’t really take into account include abilities like Pack Tactics in hobgoblins. In a regular D&D game this is annoying but not huge. In the case of a unit of hobgoblin heavy infantry, look out!

      I get that they’re trying to make things simple, but I fear they ended up being simplistic.

    • As it happens, I am a huge Cornwell fan, most especially of The Warlord Chronicles. His other works are excellent as well, of course. 🙂

      Your point about formations more or less spells out why the Romans ditched the phalanx and developed the maniple. Or, to put that more briefly, I couldn’t agree with you more. Simplification can go too far and sacrifice too much of what the user finds useful or interesting.

      I’m not yet sure how I think mass combat should work, but this is awfully useful for helping me figure that out. 🙂

    • Colin McLaughlin

      Why not just model everything off of Myth: The Fallen Lords?

    • Ish

      I think that when you stray too far from “cinematic” and PC-focused mass combat rules and start worrying too much about ranks, formations, maneuver, and other “simulationist” concerns… Well, D&D just isn’t the right engine for that. No matter how many extra rules you layer on, it’s just the wrong foundation.

      I think it would be far easier to figure out how to add the D&D PCs as heroic models to a wargaming system, then to add wargame units and tactics to D&D.

      ‘Dragon Rampant,’ by Osprey, is quick to learn, fairly inexpensive, and it unit creation rules are robust enough to handle just about anything in the Monster Manual.

    • I’m fine with someone publishing a wargame set with room for heroic action and calling it 5e’s mass combat rules. I don’t care how they get there, but I do think there’s a sufficient subset of players who want to engage with the fantasy of being generals while also playing an action hero that this is worth doing.

      To me, the idea that PCs should only play the special-forces combatants achieving objectives in the battle is like saying that movies should only ever be about the people doing the actual hand-to-hand (or whatever) fighting. There are a lot of perspectives in such a battle, all of which can reasonably be protagonists, and I want to see D&D support that.

    • Ish

      That’s what’s great about this hobby (especially in our age of easy mass publishing) there are thousands of ways to get from A to Z; So you can usually find one that works best for you and your group, and i can find one that works best for me and mine.

      For example, we’ve seen a dozen-plus articles detailing various “Domain Management” options for D&D; ranging from fairly simple and abstract, to very complex and detailed.

      Mass Combat systems in various RPGs over the decades have run a similar large spectrum.

    • Yep, and eventually I’ll write the full series of articles on the history of mass combat rules in tabletop RPGs. I’ve started the research for it, with Mentzer (somewhat mathy, but they hold up surprisingly well 34 years later), ACKS (looking at the D@W free version right now, though I clearly need to upgrade to the big-boy version), etc.

      I’m actually not sure: is there remaining disagreement to discuss, or do we pretty much agree that there can and should be one 5e ruleset for mass-combat-as-backdrop (a shorthand explanation for the L5R/Heroes of Battle model) and another for mass-combat-as-strategic-minigame (Mentzer’s War Machine rules, Birthright’s battle card rules, etc.)?

    • Ish

      Those are the two ends of the spectrum, I think.

      I just don’t feel that D&D’s basic rules are a sound foundation for mass-combat-as-strategy-game.

  • Ish

    The only mass combat rules I’ve ever enjoyed in an RPG were the ones from ‘7th Sea’ and ‘Legend of the Five Rings.’ They didn’t concern themselves overly much with units, maneuvers, and the like.

    They allowed the battle to happen largely in the background of the scene, “zooming in” on the individual actions of the hero(es), much like a Hollywood movie.

    We don’t see the units wheel and maneuver in ‘Braveheart’ or ‘Return of the King,’ and we really don’t need to. Hollywood gives us a general feel for the flow of the battle, cuts to a hero doing a cool thing, gives us another shot showing how that effected the overall battle, then cuts to a second hero doing another cool thing… until eventually one side wins.

    • I specifically disagree with your point about Braveheart. Hilariously wrong as their depiction of the Battle of Stirling Bridge is (starting with the absence of a bridge), we DO see William Wallace give orders for the mounted Scots to retreat, circle around, and annihilate the English bowmen. We don’t follow the riders’ perspective, because the movie emphasizes the tension of the Scottish nobility ditching Wallace at the most important moments, but when they do show up, we see them from very much a third-person perspective.

      Similarly, at Falkirk, much of the audience’s perspective on the battle is actually King Edward’s, who stays back and orders units to act. The battle isn’t completely from the antagonist perspective, of course, but nor is it entirely focused on Wallace, Angus, &c.

      Return of the King, particularly in its Extended Edition, also gives a pretty even balance of individual and wider perspective. We see clashing cavalry charges that aren’t from any one character’s point of view, the Rohirrim and the forces of Gondor gradually losing despite the protagonists achieving most of their apparent objectives, and finally a major arrival of reinforcements – the Dead Men of Dunharrow. There are also a good number of individual actions, but only the slaying of the Witch-King of Angmar seems to make a lasting difference. Everything else is just PJ letting Legolas’s player cause some havoc and mitigate what is otherwise shaping up to be a crushing defeat.

      Obviously, none of these battles were played out with dice – Braveheart was marginally constrained by some notion of history, and for all that PJ was willing to change, the outcome of the Battle of Pelennor Fields was not one of them. Because I’d like to be able to tell an ever-wider variety of stories, though – ahem, Birthright always comes to mind – I would like mass combat rules that achieve wargaming-style goals, rather than always using mass combat as a backdrop for PCs to show off individual prowess.

    • Ish

      Okay, perhaps I chose the wrong movies… ;^) But I think you understand the general notion I am attempting to discribe.

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