Mass combat rules

[Jeivar]

When I DM a game of 5e I would like to either do a Viking campaign or basically do barbarians vs Rome (with the PC's as the barbarians), and in either one a shield wall fits right in. I would also like have the players as young chieftains, leading troops into battle. Have any official rules been released for this, or am I going to have to make them up myself?

[Human Paragon 3]

When I DM a game of 5e I would like to either do a Viking campaign or basically do barbarians vs Rome (with the PC's as the barbarians), and in either one a shield wall fits right in. I would also like have the players as young chieftains, leading troops into battle. Have any official rules been released for this, or am I going to have to make them up myself?

There are rules in the DMG about handling mobs (X weak creatures against a PC or strong NPC) but nothing about armies vs. armies. This has always been a weak point in D&D. My advice would be to focus on small skirmishes instead of representing combats where thousands of warriors square off.

[Demonic Spoon]

My advice would be to check out the 3.x book Heroes of Battle. There are some 3.x-specific rules in there, but the general way it handles mass combat is pretty solid.

Basically, you don't try to roll out or simulate the battle. You figure out how it will happen beforehand without the players' interventions and based on what they do, the battle goes differently.

I wouldn't just have your players stand out in a field in a mass battle leading troops - the ruleset doesn't really lend itself to that. Instead, they should have smaller, more concrete goals, even if that goal is in the midst of a full-on battle (scale the wall and secure an important tower, assassinate the general, destroy their siege equipment, etc).

[Envyus]

Unearthed Arcana should have Mass Combat rules. So we should get it eventully

[Jlooney]

I don't see this being something you can do till epic level because one of the building blocks of 5th is that low level creatures are still a threat to high level pcs.

However I do like the idea of objectives during the fight. Kinda like if you take out this cannon group b will be able to overrun group a in 3 rounds.

[Daishain]

If you do use 3.x mass combat rules, bear in mind that large scale combat is FAR deadlier in this edition. React appropriately.

[GiantOctopodes]

When I DM a game of 5e I would like to either do a Viking campaign or basically do barbarians vs Rome (with the PC's as the barbarians), and in either one a shield wall fits right in. I would also like have the players as young chieftains, leading troops into battle. Have any official rules been released for this, or am I going to have to make them up myself?

One of the best tips I ever received in a DM panel was this: *Don't* run large scale, NPC on NPC combat. Rather, run it like a movie- outline the scope of the battle in broad strokes, and then zoom into the PCs, facing their own baddies- perhaps the leaders or champions of the enemy army, perhaps a representative swath of the troops appropriate to level, or whatever else. Between rounds or randomly interspersed between actions, give brief narrative descriptions of the battle raging around them and the acts of derring do they are witnessing from the rest of the army, but otherwise have the forces beyond what they are actually dealing with non-interactive set pieces. It's called "representative combat", and it helps a lot.

A few other tips:

1) Give players ways to impact the overall battle beyond just combat. Point out situations they see wherein their aid can turn the tide. Maybe there is a gate that needs to be broken down which is well defended, maybe there is an archer position that needs to be overrun, maybe there is an enemy flanking maneuver that needs to be foiled, or whatever else. Don't be afraid to cut from "scene" to "scene", skipping generic battle in between and focusing on the key moments.
2) Have the tide of the battle overall swinging in such a way as to mirror the player's overall success or failure. Make it so their efforts truly are a microcosm of the battle at large, shown by your narrative descriptions.
3) Don't be afraid to have some things be outside the PC's control, they're not the be all and end all of this combat. If you do want to figure out how the overall combat fares with a few dice rolls, feel free. It's an abstraction, it can be a bit rough. One easy suggestion is to make an attack roll for each side, with advantage being given out as appropriate (properly executed flanking maneuvers, vast numerical superiority, whatever else). The side that beats the opponent's AC by a higher margin (or misses by a lower margin, as it may be) wins that "quarter" of combat. Roll a d10, that percentage of troops are lost on the losing side. Do that 4x, and you have your results.
4) Make sure the PC's maintain motive power. If their forces are going to lose this battle, despite their valiant heroics, because they're underequipped and undertrained, outmanned and outmaneuvered, or whatever else, that's fine. But even if the derring do of the heroes doesn't win the day, it should turn a massive rout into an organized retreat, or prevent massive losses, or disrupt the enemy supply lines or pursuit, or achieve at least some sort of victory in the face of defeat, like killing a leader of the enemy army.

Hope that helps!

[rlc]

One video game I played had this part of it where you were teleported into the emperor's palace to assassinate him and there were, of course, several guards who came to fight you because they obviously didn't want you to do that. However, if you decided to rest while in the palace or tried to just escape (or you were missing a certain item needed to use the teleporter that opened after you did manage to kill the emperor), you'd get overwhelmed and a screen would pop up saying that you died. You didn't have to get hacked to bits, the game just told you it happened.
This idea can be used in this type of situation. There would obviously be plenty of soldiers for you to fight on your way to your objectives, but if you went out of your way to kill everybody instead of doing your special ops mission to smooth out the combat, then you'll just get told that you died of a million papercuts.

TL;DR: I agree with everybody else, but I also think you should be prepared for the party wanting to kill everybody, rather than just the guys standing immediately in the way of their objectives.