wave based encounters

How To Use Wave Based Encounters Step by Step

In a previous quick tip article we mentioned wave based encounters as a method for handling issues with party balance. There were some questions about wave based encounters and it seemed people didn’t know how to set up or run them. This quick tip covers how to use wave based encounters step by step.

Setting up Wave Based Encounters

Step 1. Design the Base Encounter

We’ve talked quite a bit about encounter design in other articles, but your first step is setting up an encounter like normal. In this step you will choose your location, your first set of enemies, and build out your battle map. Keep in mind you are designing this for waves, so don’t make this a boss level challenge unless you are dead set on a total party kill.

Step 2. Build Your Waves

A wave consists of an additional group of monsters that join the battlefield at a certain point. To build a wave you should take the monsters you used for the base encounter and theme the wave around that. For example, if you’re using goblins already, each wave could consist of additional goblins. If you’re running a complex encounter with undead, each wave could consist of a mix of undead creatures.

When choosing the creatures for a wave, the total CR of those creatures should be equal to approximately 1/2 of the original encounter strength, and never more than total CR of the original creatures. We’ll touch on why in the next section.


Step 3. Choose When Waves Occur

Waves of creatures enter the field at a certain trigger. It could be when creatures in battle call for reinforcements, it could be after a set number of rounds, or it could even be after each wave is defeated. This has to do with the overall CR of the waves. If you are adding waves that overlap, the CR increases with each wave sharply. If you are adding creatures after each wave, or replacing creatures that are defeated, the CR still rises, but more slowly and only due to the length of the encounter.

Choosing the right trigger for when you add creatures depends on the difficulty you are attempting to generate and your reason for using waves. If you’re doing this as a longer combat encounter for story narrative, then try to keep difficulty scaling lower. If you’re doing this to balance combat or force cooperation in a group, difficulty scaling can be a bit steeper.

Step 4. Deciding on Wave Entrances

The new waves have to spawn somewhere. You can have them enter from just about anywhere, but it’s best to give yourself multiple options. In open field encounters they simply come in from the edge of the battle map. However, in closed rooms or dungeon maps you need to decide on location that creatures can enter from easily.

You can place these in a minimum of two locations spaced out on the map, and do not indicate the locations initially to the players. The strengths of wave based combat come from resisting zone control from the players, so monsters spawning in various locations helps towards that end.

Step 5. Choose an End State

The players have to be done with combat at some point. It could be after a certain number of waves, or it could be they need to collect something from certain enemies to be able to escape. Whatever you choose, it needs to be defined in someway so that your players have an out and death isn’t 100% certain.

There is always the possibility that you are looking to overrun your players. As an example you may want to get the players into a prison cell somewhere. A wave based combat is a good way to achieve this if your end state is when all the players are defeated. You don’t tell your players this, and they could potentially escape still, but waves work to eventually exhaust and collapse the team. I’ve used this to good effect when having players wake up in a dungeon somewhere after they were defeated in combat.

However, if your team keeps wreaking your waves, don’t force your story on them. It takes the wind out of players’ sails when they’re doing a good job but know they’re in an unwinnable scenario. Readjust your ideas to get your heroes where you want them next in a way that doesn’t punish the players.

Step 6. Calculate and Award EXP

Using waves based encounters can make things get complicated really fast. You don’t know for sure how many enemies your team is going to fight and you have to scale EXP based on the length of the fight. The easiest way to do this is to use a calculator. Kobold Fight Club is great for this, but there are a ton of options. If you want to do this manually, you can use the instructions in the Dungeon Master’s Guide on page 82.


Using Wave Based Combat In Your Game

Waves offer interesting alternatives to standard combat encounters and have a lot of fun uses. Hordes of undead, skirmishes in a war, or an onslaught of castle guards. There’s plenty of ways these can be used in your game. It’s not an exact science, but it’s easy to adjust. Wave based encounters are flexible, so you can ramp up or slow down combat easily with this approach. You will usually have much more fine-tuned control of the combat itself.

It can be difficult to keep track of all your enemies and initiative, but it’s nothing good organization can’t fix. If you’re going to try out wave based encounters, make sure your encounters are well tracked. Use an erasable white board for tracking initiative position and monster stats. You can also keep a full set of combat tactic notes for each creature used. These aids really make these combats much easier to handle and keep them running efficiently. Even still these fights can take hours, so be prepared for that.

Try Wave Encounters Today

We hope this quick article has been informative on how wave based encounters are set up and run. There’s a near infinite amount of variety that can be used with these types of scenarios, so if you have any questions, reach out to us! Let us know if you’ve used wave based encounters in your own game on Twitter.

As always, Happy DMing!


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