My players (level 12-13), through a series of... decisions, have ended up in a situation where they and perhaps a few hundred to a thousand allies will be facing off against a garrison of several thousand varied troops.

To resolve this, I was considering using the latest version of the Unearthed Arcana mass combat rules. However, mass combat is a significant departure from the usual D&D 5e gameplay, and UA rules have not been playtested and refined the way published rules are.

How well do these rules work in practice?

A good answer will draw from actual experience using these rules, and address the following criteria:

  1. Time: One of the stated goals of the UA is to do mass battles quickly. Does it succeed? Are mass battles "quick," or do they seem to drag on forever?

  2. Player Agency: Can the players make a significant difference in the course of the battle, in either direction? That is, if they make poor decisions, can those result in a loss, and if they make good ones, can they win the battle?

  3. Complexity: This is a secondary issue, but how well did your players take to the new rules? Mass Combat rules are quite different from ordinary combat--was there a lot of stumbling over rules at the table?

For those considering a frame challenge, I'm aware that I can resolve this issue differently, without having to resort to a new set of rules, but I'm exploring this option specifically. Still, if you have any specific warnings, I'd like to hear them.

  • \$\begingroup\$ Here's a meta question regarding the topicality of this question. \$\endgroup\$
    – Icyfire
    Commented Jan 31, 2018 at 18:25

2 Answers 2


In case no one here has first-hand experience using those rules, here is a Reddit post discussing the topic and it's flaws, as well as an alternative.

The OP there argues that the system is very slow, players don't have that much control on the morale of their allies and focus is withdrawn from the players because of the complexity of handling the armies calculations.

You might consider using War Machine, an old system, but one that is reportedly well suited for 5e.

An excerpt of the post:

For a several months now, my party of level 10 PCs have been on a collision course with one of the main factions of the large island the campaign is set on, and tonight things finally came to a head with a clash between their slave rebellion an contingent of the evil conquistador oppressors they are struggling against. Everyone was excited to see the fruits of all of the resource gathering, recruitment, politicking, and sabotage the campaign has focused on since beginning this arch, and the strike a decisive blow for freedom. Tensions were high as their forces of nearly 10000 untrained, poorly armed rebels prepared to give battle against a contingent of just 2000 professional soldiers, and there was serious discussion among the players about whether losses would be too high. But no, for the good of these people and their families who were seeking sanctuary in the nearby Fey jungle, these forces MUST be defeated. Alright, your soldiers are ready to fight and die for their freedom let's do this....and we did.

I first got an inkling of of how "off" this system was when I saw the completely 1 sided nature of the Battle Rating (BR) system. Their army of escaped slaves were each effectively Tribal Warriors, CR 1/8th, while the enemy's army was composed of professional soldiers, CR 1 with some CR 3 veterans serving as sergeants. With the limit of 400 individuals/unit, that meant that each unit of slaves had just 20 BR, while the soldiers had 250 BR. For anyone who hasn't read the rules, Battle Rating serves as a unit's main stat, and is used for both offense and defense. When an attack is made, both the attacker and defender make opposed BR rolls. If the attacker wins 1-10, the defender loses 2 BR. If they win by 11 or more the defender loses 5BR AND makes a Moral check to avoid fleeing the battle (more on Moral in a moment). As should be pretty obvious, the maximum roll of a d20+20 is 40. The lowest roll of a d20+250 is 251. There was no way that the slaves could EVER harm the professional soldiers, regardless of numbers. Maybe that is intended to make for cool 300 style stands against superior numbers, but when the PCs are the inferior forces, it feels like throwing people they care about to the slaughter. But ok, the PCs did a pretty good job of convincing some powerful groups to join them. This can just be a fight between the PC's strike squads and the enemy army. A little creative behind the scenes number crunching later (the PCs don't know the CR of their allies) and they are slight underdogs, but only by a bit. Or so I thought.

The second issue that quickly became obvious is how one sided the Moral system is. Moral is determined by a number of factors, but is basically "how likely is your force to stand its ground" and is modified by the Charisma of the commander of each unit. Whenever a unit loses a fight by 11 or more, it needs to make a Moral check with DC 10 or be routed. For professional fighting forces with remotely charismatic commanders, Moral should always be 5+. For a bunch of escaped slaves, the PCs had to pull out all the stops to just avoid negatives. At first this seems ok, so what if a few units break? As long as the groups that the PCs are part of (with their super human charismas) don't fail then the battle is still fine. The problem comes with the rule calling for Moral checks from EVERY allied unit within 500ft when a unit flees or else lose its next action. We've already established that the escaped slaves will always take heavy losses from a single attack, and with 0 Moral, they have a 50% chance to break. If they do, every other unit remotely nearby has a 50% chance to lose its action. In a fight were there might be 10 enemy units, each slave group in the area might have only a 1/32 chance to actually get an action, not just cower. More importantly, the important groups that the PCs have joined need to make these checks too. Even with a solid Charisma, they might have a +7 Moral. With 5 checks a round, there is better than a 40% chance that their pet unit isn't going to get a chance to do ANYTHING the next round.

You notice how I mentioned that the scale for Morale checks is 500ft? Well that is the next issue with the system: movement and distances scale by 10, but ranged weapons remain the same. In standard combat, it takes 10 rounds for someone to close to melee range with someone using a longbow. This makes killing fields horribly deadly and a serious deterrent to a frontal assault. In the Mass Combat UA, a round is assumed to take a full minute, which means the archers only get a single volley off before being forced into melee. For other ranged weapons, enemies can actually dash across the entire killing field without ever taking a shot.

But quite frankly all of those issues seem like little gripes, and could be worked with. The single BIGGEST issue with the system is simple: all of the rolling, tracking of BR and Moral, and movement around the map completely removes the focus from the PCs, which is what the game is meant to be about. A single PC's action might take 40-60 seconds of session time, while a single turn for a group of units could easily take 4-5 times as long between movement, making contested checks, moral checks, and then moral checks for everyone else in the area. Where the PC might roll 3-4 dice on a turn, plus a few from the DM for saving throws, the army units EASILY roll 20 dice in a turn, often with many different modifiers. Add in keeping track of which units can and can't act, and the book keeping becomes incredibly tedious.

And at the end of the day, there is absolutely zero payoff for all of this work. In a strategy game, careful deployment of troops, good use of tactics, and clever ploys can turn the tides of battle. With the anemic BR system, positioning only matters in cases where there BRs are within 19 to start with, which is extremely uncommon except in specific cases. In all other scenarios, there is no room for strategy, only for ramming your head against a wall, doing pointless book keeping, and stealing the spotlight from the characters the PCs actually care about.

  • 2
    \$\begingroup\$ I've edited in the contents of the linked reddit post, though one of you may want to edit it down to only the most relevant information. \$\endgroup\$
    – V2Blast
    Commented Feb 1, 2018 at 4:41
  • \$\begingroup\$ It may also be helpful to include some of the information from the comments, particularly this: "A fix lots of people seem to be missing: BR doesn't go above +50 when applied to rolls. Any extra BR acts a as kind of HP system, meaning if you get hit a couple of times you'll still have +50 to your BR rolls. This is a lot more fair, and can lead to interesting tactical decisions about how many units you want to add over the limit to flesh out the BR "buffer"." \$\endgroup\$
    – V2Blast
    Commented Feb 1, 2018 at 4:44
  • 1
    \$\begingroup\$ From what I read from the reference, the GM and his players have clearly no idea of tactics... frontal assaults with low-quality troops... Seems pretty clear to me why it's a bad idea. VERY SUBJECTIVE \$\endgroup\$ Commented Feb 1, 2018 at 13:57
  • 1
    \$\begingroup\$ @JPChapleau Question is "How well do these rules work in practice?" and not "How to properly plan a mass combat?". Linked post is purely anecdotal, but shows issues that may arise from using these rules. \$\endgroup\$ Commented Feb 1, 2018 at 14:40
  • \$\begingroup\$ It seems to me that my players' situation will be the opposite of this--they are the ones with the small number of highly trained troops, fighting a larger, lower CR army. \$\endgroup\$
    – Icyfire
    Commented Feb 1, 2018 at 18:14

They work fairly well, with some reservations.

After using these rules, I felt that while the rules worked pretty well in general, they were not without some hiccups and omissions. Ultimately, though, I feel like they don't mesh well with D&D's PC-focused rules.

The rules did pretty well on the time and complexity criteria. While it was a lot of rolling, I did not feel like it took excessive amounts of time to run a round. Reducing all the normal gameplay statistics to a single number, BR, helped a lot for complexity as well.

However, interactions between the PCs and the larger armies required me to make lots of judgment calls. My players first teleported into the city, to take out a specific unit, and then joined the larger fray afterward. I felt like the portion of the battle where the PCs were fighting a specific, small unit worked best. I could run the PC's encounter and the larger skirmish at the same time, which made the battle a great context for the PC-focused fight.

When they joined the larger fray, though, I had a lot of trouble merging the mass combat rules with the PC rules. For example, how do I resolve a melee character attacking a unit that was attacking another unit? That sort of lies at the interface between the mass combat and the individual combat rules. I ended up making a lot of judgments like that at the table, and I'm not sure if I'm satisfied with them.

If I were to use these rules again, I would spend more time planning PC/unit interactions. I think that it could be made more fun, but the UA rules don't provide much guidance in this area.

Specific Concerns

I also noticed some specific things about the rules:

BR scaling: I tried making an army of mostly low-level guards, with a handful of elite priests. However, the low-level guard units have very low BRs, and the high-CR units have high BRs. Given that BR is capped at +50, there are basically two types of units: ones with BRs < 50, and those with BRs > 50. Units with BRs >> 50 are essentially untouchable. This is a departure from usual D&D, since a CR difference from, say, 1/8 to 1/4 is very small, but it's quite significant for mass combat. Additionally, BR can only drop by a maximum of 5 per attack, which felt super slow for high-BR units. In the future, I would try breaking up the units so that the BRs don't exceed 50 by much.

Morale: I wish there were more guidelines for morale, especially for morale changing during the battle. Failing a morale check is the primary way for most units to be removed from battle, and morale doesn't change much throughout the battle. Thus, the battle felt pretty static throughout, with units dropping out mostly due to unlucky rolls. It would be nice to have more of a sense of progression, somehow.

  • \$\begingroup\$ Thanks for bringing your experience back to share with us in a well-formulated answer! \$\endgroup\$ Commented Feb 20, 2018 at 23:07
  • \$\begingroup\$ Have you considered using the morale system from Chainmail, 3d edition? \$\endgroup\$ Commented Feb 20, 2018 at 23:35

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