D&D 5E Running several combats in a row

[Nightfly]

Next week I'm planning an encounter for my players with a military assault theme. The party will have to fight through 3 or 4 waves of enemies without a chance to rest or retreat.

Given how shaky 5e is in terms of encounter balancing, I'm wondering how best to set this up. I want the battles to be very tough but winnable. I've found 5e Challenge Rating to be a dicey metric under the best of circumstances, and since 3 or 4 fights in a row without a rest is outside the game's assumptions, I'm worried my setup will turn out to be way harder than CR would suggest. Do any of you wise ENers have any tips on how I can build this kind of encounter to be challenging but not impossible?

 

[Lakesidefantasy]

Plate mail armor and shields for everyone. Then put the wizard in some sort of canister on legs.

 

[Burnside]

Make it clear to the players from the outset that they'll be dealing with multiple waves of enemies with no opportunity to rest in between. They'll at least then know they need to ration their resources.

 

[Zaukrie]

I recently did this with waves of undead. It was a bit challenging, but I'm a fudger, so I made it hard and they almost died at one point. If you don't want to fudge, you can have NPCs kill a bunch of baddies somehow at some point, like the minions around the better fighters/archers/wizards bad guys (if that is in the story).

I used a die to determine how the NPCs did in a fight like this once, the players knew the NPCs needed a 12 or something in the last round to kill off enough enemies that they could make it. I'll see if I can find that encounter in my notes.

 

[Zaukrie]

Make it clear to the players from the outset that they'll be dealing with multiple waves of enemies with no opportunity to rest in between. They'll at least then know they need to ration their resources.

100%

 

[Zardnaar]

Deadly encounters aren't actually that deadly with the numbers multiplier.

So depending on level.....

Bulk fodder is exactly that.

 

[Koloth]

Important question: Does the party know this is coming? If so, they should prepare accordingly and during the encounters, expend non-renewable resources sparingly. If not, given how so many RPGs these days assume full or near full rest after each encounter, it will probably go badly.

Assuming they know, give them access to extra healing, lots of standard ammo, and such. The archer running out of arrows during wave one would be a bad thing.

Have a plan that allows for retreat even though you said no retreat. Unless a TPK is an acceptable outcome.

Is the party on offense or defense? Offense has a bit more control over cadence then the defense. But an offense that pauses too long may find themselves on defense.

 

[jgsugden]

I do this all the time. It is one of my go to techniques when following the guidelines for encounter design in the 2014 DMG. PCs are intended to be able to handle multiple 'waves' of enemies with no rest - but you do want the encounters to follow the guidance in the DMG. You want them to mix in easy, medium and hard waves in with a deadly.

You do not need to give them a clear expectation there are waves of enemies coming. Doing so takes them out of the moment. It makes it seem more like a board game and less like an RPG. They should be discovering what is coming as the story dictates. If they scout and put effort into gaining information, let them be rewarded for that as it makes sense. If they just sit back and let whatever comes come ... don't give them any information they did not earn. Realizing they used their best spells but that there is more to come can be a moment that they'll remember. Don't deny that by giving them a preview.

Make sure the waves make sense. It shouldn't be that the enemies arrive in waves for no reason. If it would make sense for them to all gather up and then attack at once, look at the situation and think about a good reason within the story they might arrive in waves. They might be trying to achieve multiple goals and some of them may arrive to the fight with the PCs late because they were off doing their first goal, for example. You want these waves to make sense rather than feel like the next wave in an 80s space themed arcade game.

Treat these wave encounters like other encounters. Put secondary objectives for the PCs to achieve in the battle. Are there people that need to be protected? Do some of the enemies (try to) flee with something they took? Does an enemy leader begin casting a ritual that the PCs need to disrupt? Do they get a short window at taking out an important general? Make the waves feel different.

Finally - wave combats often take place near each other, or in the same location. Give the location some dynamics. Part of it might collapse during the waves. There might be a fire spreading throughout the waves that causes things to change. Have enemies use spells that impact the battlefield or bring in monsters with big corpses that change the situation. You want the whole series to feel like it is evolving - not just a tower defense game.

 

[Nightfly]

Important question: Does the party know this is coming?

Yes. They'll fly onto an enemy tower and fight their way down. They don't know exactly what it will entail (actually, at this point, neither do I!) but they'll be clear that they will be fighting several waves in succession as they try to descend the tower and the enemies try to stop them.

 

[Flights of Fancy]

Do any of you wise ENers have any tips on how I can build this kind of encounter to be challenging but not impossible?

Set it up according to the narrative of the world and don't worry about it.

If it is beyond the PCs, the players need to recognize that. If it ends up being too easy, so be it--let the PCs shine.

But through CRs, balance, and everything else out the window.