Battle vs horde of weak monsters, how to make this fun?

[Ancalagon]

Hello

I'm currently running a large dungeon from 2nd ed (The Gates of Firestorm Peak) and I'm converting it to 5e. It's been going well so far (it's a good adventure, with only a few small errors) and in general converting from 2nd ed to 5e is not very difficult, although there is one problem – cannon fodder. Because of bound accuracy, cannon fodder is more dangerous in 5e – even a lowly goblin has +4 to hit, while in 2nd ed they would have the equivalent of +1 or even +0 to hit.

The party has passed a major milestone, and I am getting the next segment ready. There is one big battle happening soon-ish, and there is even a big map printed for it as part of the adventure (imagine a long 20 foot wide corridor with a few obstacles and *lot* of side passages). And well... it's 95% cannon fodder, and I'm not quite sure how to run this properly in 5e.

The party members are all level 6 and consist of a paladin (ancient), cleric (knowledge), warlock (tome/old ones) and monk (fist), along with 2 semi-useful NPCs

The foes: one HUNDRED gibberlings. The gibberlings are basically demented angry humanoid, think the tasmanian devil from loony tunes, with the fighting power of a goblin. Individually, they are very weak, but there are so many of them. There are a few brood gibberling (tougher gibberlings that can spit brain slugs at people) but 95% of them are the "regular" kind.

How do you run a horde of weak creatures and have the challenge work? I see potential problems here:

1: if I "convert" the to hit number, with so many incoming attacks the PCs are going to take a lot of damage. Combine this with any sort of pack tactic (pushing, shoving, grappling etc) and it's going to get super messy and potentially TPK territory

2: However, if the cleric casts spirit guardian, the area of effect damage will obliterate any gibberling that comes into range – even if they make their save, most of them will die from the damage due to low HP. The rest of the party will easily be able to mop up the few that manage to make it through.

3: Killing 100 monsters seems tedious (I intend to have many of them run away when it becomes obvious that they can't win).

Any advice on making this battle fun/interesting would be welcome

Thanks!

Ancalagon

 

[iserith]

Create a Huge or Gargantuan swarm-trait monster that represents dozens of gibberlings. Use however many you need to make that a challenge of the difficulty you want. When it gets to half hit points, it does less damage as per regular swarms. When it gets to 25% hit points, it breaks into X number of individual gibberlings.

 

[The Crimson Binome]

Instead of rolling dice for the enemies, assume average distributions of the d20. If they need a 17 to hit, then four out of every twenty will hit. If they don't have ranged attacks, then only eight of them can surround each PC. (Ignore the possibility of shifting ranks.)

If they're as squishy as you imply, then just track whether they are up or down. Successful attacks kill one, and a fireball kills ~30 of them. Feel free to play fast and loose with the exact numbers, in order that it won't drag on. It probably won't take as long as you fear.

 

[Warmaster Horus]

The Unearthed Arcana rules for Mass Combat might help.

https://media.wizards.com/2017/dnd/downloads/2017_UAMassCombat_MCUA_v1.pdf

 

[Morrus]

Use minion rules and have them be one-hit kills as the PCs wade through them?

 

[Monayuris]

Yeah the DMG has a chart for hit distribution for mobs.

Also use the cleave rule from he DMG. Which allows you to apply left over damage to another nearby creature after dropping one to 0 hp.

Alternately... A retro-clone Adventurer Conqueror King has a cleave rule where you get an extra attack after dropping a foe to 0 hp. You get a number of these extra attacks equal to your level.

It’s not uncommon for a mid level fighter in ACKS to drop 5-10 low level foes in one round.

 

[Dausuul]

With a scenario like this, my advice would be to play it fast and loose. Don't think of it as a combat encounter, because it isn't, really; there's no way to win a "fair" fight against a hundred foes. Rather, it's a challenge to the players to figure out how they can take down the horde. If you normally do fights on a battlemat, consider skipping it and going theater of the mind, to encourage a focus on clever solutions rather than dice and minis.

Obviously, if the cleric casts spirit guardians and the gibberlings charge into it, that will do the trick. You could simply let this work, in which case it will be a very short encounter and everyone just moves on. Alternatively, you could give a few of the gibberlings ranged attacks; the cleric burns down most of the horde but then faces a barrage of darts and rocks to disrupt his/her concentration. Whatever you do, don't worry about "cheaty" solutions. The whole point of an encounter like this is for the PCs to come up with a cheaty solution. If they don't, they lose.

 

[Monayuris]

Also, think about terrain.

Put in a choke points or areas of high ground / low ground. Make the area of the battle offer tactical choices.

 

[Monayuris]

Actually looks like the terrain is already set. Those side passages, though? Do they allow for looping or flanking? If so, have your horde take advantage and show that there maybe tactical uses for those side passages that the players can exploit.

 

[Ralif Redhammer]

One hundred Gibberlings. If I recall the 2e stats, there thing is coming in hundreds.
With large groups of monsters, yeah, if they got swarmed, the sheer number of hits can wear the PCs down. And even if they don’t, it can easily become routine. On the other hand, these sorts of encounters give the AOE folks time to shine when they take out whole swaths of foes.

I don’t know how much leeway you have with that section of the module, but I’d recommend the following:

1 - Give lots of things for the PCs to interact with, like chandeliers they can drop on the Gibberlings, barrels of explosives they can trap and trigger, weird wizard stuff that does who-knows-what.

2 - Have the combat environment change throughout the combat. Maybe a section of ceiling, floor, or wall collapses under the weight. Or the blood turns everything into difficult terrain. When in doubt, set everything on fire and see what happens. If those Spirit Guardians are creating a choke point, this is a great way to mix things up.

3 - If there aren’t enough AOE abilities, put some ballistae or magic cannons (limited use, naturally) where the PCs can get to them.

4 - Allow them to use strategy and plan. When their plan works at first, they'll cheer. When an unexpected complication forces them to adapt, that will create tension anew.