These are my own homebrew rules that I made up because I wasn't satisfied with what was out there.
Previously I had tried the "When Armies Clash" Unearthed Arcana which I didn't like. I also tried "Mass Combat" which was too crunchy and slow as far as I'm concerned.
I also tried Matt Colville's rules for armies in Strongholds and Followers, but I didn't like the dice pool mechanic that he uses. It requires too many dice and it's weird to bolt a system that's not d20 on to a d20 system.
I don't use DnD 5e to do things DnD 5e was clearly not designed to do.
Ironically, wargaming is actually something d&d isn’t pants-on-head retarded about. It’s just regular retarded about it. I ran a regular fight with every monster counting as a unit, and it worked okayish. Players could fight portions of a unit, and remove their combined CR from its hp on a win.
Are you trying to bolt a wargame onto D&D? Or are you looking for a system to abstractly figure out the result of a larger battle in which the PCs play a small part?
Your design goal is important.
I just want an abstract and quick way to resolve large battles. I'm trying to balance speed and accuracy.
Come up with a combat resolution table with a handful of modifier types - lets say numbers, terrain, morale, and supply. Stick to 5e's +-2,5,10 and adv/dis. Probably break your CRT into buckets like like Tie, Win/Lose, Win/Lose by 5/10,
I just adapted the mass battle rules from Savage Worlds and made it a skill challenge.
>mass battle rules from Savage Worlds
Where can I find these?
They're in the Savage Worlds Adventure Edition core rulebook. Should be in the share thread. The rules are light but should be enough for a lot of people.
If you put a gun to my head and made me run 5e I'd probably try to adapt Cry Havoc for 3.5 as best I could.
Or just use horde/mob rules and call it a day.
Don't bother with rulesets written for 5e. Just go find an actual light wargaming ruleset you like and then use it whole cloth in the middle of the session, plus let your players use whatever shit they've got in 5e as you see fit per GM fiat if it makes sense.
Make an army swarm-type creature
I would never play 5th ed. but if I had to, I would either adapt the original AD&D Battlesystem, or just use the mass combat wargame that D&D was adapted from, Chainmail. . Why try to re-invent the wheel?
You saying players taking part in a battle are 1 bad roll away from death?
Even if not death but just being wounded it still sounds bad.
Even if things are heavily abstracted I'd still like if you had a unit of, say, Veteran Heavy Dwarf Greataxe Infantry that each of those 5 words meant something.
How much does the battle matter and how much influence does the party have over it? If the answer is not much, I just bullshit it by giving each army a bonus depending on how strong they are and roll d20+bonus against DC10+enemy bonus both ways. If one side wins and the other loses then then it's deceive, if they both win/lose then minor/major losses and roll again in a turn. If it matters then I go look at the BECMI war machine rules again.
Armies (or more precisely, the units within the army) are swarms with thousands of HP, and probably area damage as an action instead of attacks. Important things within the army are "lair actions" of the swarm, Stuff like commanders issuing orders, warmachine volleys, elite units, whatever. If the PCs decide to deal with the "lair action" it turns into the adequate encounter/combat with a narrower focus, and the "army" becomes the lair action.
At some point you start rolling WIS for the army/units routing (aka get the frightened condition and dashing) on a fail.
Have you tried not playing D&D?