This post examines encounter types and proposes one that you might not have come across: the portable encounter.
Encounter types: fixed-location and random
Most encounters in published adventures are fixed-location. Enter room 3 and meet the troll that lairs there. Or don’t, and don’t. But if you, as GM, stick entirely to fixed-location encounters, that limits your control. Pacing and sequence depends on what the players choose to do. And, depending on the whims of the dice gods, the adventure can turn out frustratingly hard or all too easy for the PCs.
If you plan on having a certain encounter or scene, it depends on getting the players to a certain place. The temptation is to railroad them there, but players often dislike this, unsurprisingly—they want to choose their own adventure. Also, the world tends to feel very static, with all the monsters just waiting in one place for adventurers to kick in the door.
But RPGs also often have random encounters. Every hour (or day or whatever) in a monster-haunted area you (the GM) check randomly for ‘wandering monsters’–roll a d6 and on a 1 (or whatever) monsters approach. What monsters and how many is also rolled randomly, with the 5e DMG offering things like: in a sylvan forest roll d12+d8; on a 4, encounter 1d4 gnolls and 2d4 hyenas. OK then—open the Monster Manual.
This randomness pretty much ensures that the encounter has little connection to the adventure plot. It challenges the GM to improvise (which some like, but some don’t) and it may disrupt your session pacing.
I think there’s a middle ground: portable encounters. They are not fixed to a location, and they can relate to player choices and the course of the story in various ways. But they are planned and they appear at the GM’s discretion, not randomly.
Why use portable encounters?
To look in a little more depth about why and how to use portable encounters, I’ll look more generally at why and how to use any encounters. There are actually some really useful ideas on encounter purposes in the 5e DMG in the random encounters section. But I’m expanding these to be more general.
To set scene, atmosphere and tone
Encounters (whether fixed, portable or random) can showcase a creature or character that establishes atmosphere for your world, or theme or tone for the current adventure. Your descriptions and what encountered creatures do and say can add to this and give information about your world. If you use portable encounters, you can provide this kind of flavour reliably without worrying about whether your PCs will choose to visit a certain fixed encounter, or having to adapt the tone of some random critter from the monster manual.
To tell the story
As well as the setting, encounters can reveal information about the plot. Details like creature type, character identity, dialogue, or objects or documents discovered via the encounter, can reveal specific clues, plot points or establishing facts.
There’s a particular subset of this function that is addressed in the DMG random encounters section: to give clues about upcoming encounters. Specifically, to foreshadow danger or to provide hints that will help the adventurers prepare for the encounters to come. With fixed and portable encounters as well as random, early/minor encounters can be a good way to give clues ahead of a big showdown. The climactic encounter will of course be tougher and more spectacular; by giving the PCs a chance to prepare themselves, you reward engagement and smart choices.
You can also use portable encounters more generally in storytelling. They can provide exposition, development or resolution to parts of the story or the whole thing. Their portability lets you make them happen in response to plot developments other than the arrival of the PCs at particular locations. They can happen at certain times, or they can happen as a result of certain PC choices or other events. They enable you to get early revelations in a useful sequence without railroading the PCs to certain locations.
You can use portable encounters to provide clues about who or what to go after, and where to find them, to resolve the adventure. This means you can make the climactic encounter fixed-location, which enables you to use the terrain to make it more dramatic, memorable and exciting. It also lets the players choose to go to the climactic encounter rather than stumbling across it.
For pacing
Portable encounters are particularly useful for pacing. The 5e DMG suggests GMs use “random” encounters to create urgency, to counteract the players slowing down, to interrupt a rest stop, to liven up a long uneventful journey. Note that these are reasons to *choose* when “random” encounters happen, or at least when they are checked for. The function depends on the encounters *not* being entirely random.
You will want your sessions to have a mix of action and quieter elements, ideally in a satisfying pattern of raised and lowered drama. You can use portable encounters to insert action and drama into what could otherwise be excessively long lulls.
On the other hand, if there has been a lot of drama and you feel it is time for a lull, or if progress has been slow and you need to speed things towards resolution, you can leave out a planned or potential encounter. The DMG has several points about when not to use random encounters, including not distracting from the main story, not interrupting progress, and not becoming tiresome. These are all obviously also reasons to hold back portable encounters.
If for these reasons you find yourself omitting an encounter would have given some important piece of information or item, then you can put that back in at some point via a portable encounter—either the originally-omitted one in a different context, or a different one that achieves the same purpose.
For balance
You probably want your PCs to be challenged and not to find the adventure easy. On the other hand, you want them to have a fair chance of success and not to find the adventure too discouraging.
You can use encounter planning, especially portable encounters, to adjust the adventure challenge up or down. If things are going smoothly, either because you over-estimated the difficulty of your planned encounters, under-estimated your PCs or just because the dice favoured the players, you might want to increase the challenge by adding an encounter that takes away a bit more of the group’s resources.
But if things are going unexpectedly badly for the group, you might want to make things easier. You can have one encounter less than you originally planned, or you can add an encounter with a helpful creature or NPC who heals, gives resources or gives information to help the party best use its resources.
In both cases, portable encounters are helpful, because they are easy to add or take away. Your fixed encounters provide a baseload, and the portable encounters are a good tool to adjust on the fly.
Note that you can combine fixed and portable elements into one encounter. A location can contain a fixed encounter, which you estimate to be on the easy side. If, part way through the encounter, you do want to make it harder, you can add a portable element–either a second wave of the original encounter opponents, or a different kind of opponent that joins the encounter, taking sides against the PCs. If even your original encounter is going badly and you want to help the PCs, you could introduce an ally.
To enable meaningful choice
Games are better when the players have agency: the chance to make meaningful choices. For portable encounters, this means they should be able to reduce the encounters they face by using stealth tactics, keeping to safer areas or progressing without delay. If they behave in opposite ways, then you can legitimately use portable encounters to provide consequential danger and expenditure of resources.
Portable encounters can also provide meaning to choices within the plot. For example the PCs may have the choice whether or not to antagonise a powerful NPC like a noble or crime boss. If they choose to do that, you can then have the boss send minions in response. Or if the PCs make it known that they are looking for something, then that may trigger NPCs to approach them offering help. With portable encounters, these consequences do not rely on the PCs visiting a certain location.
However, note that misusing portable encounters can work against meaningful choice. If you use portable encounters to ensure that the PCs inevitably run into a particular sequence of dangers, information and other experiences then where is the player agency?
It is a fair point. You should not make your adventure entirely out of portable encounters that will hit the PCs regardless of their choices. There can be some plot-critical encounters (probably a minority) that you plan to happen, more or less whatever the PCs do and wherever they go (for which purpose portable encounters are ideal), and other encounters (ideally a majority) that the PCs can to some extent choose (which can be fixed-location or, as noted above, portable). The type I like to minimise is encounters that the PCs stumble over as a result of random rolls or arbitrary choices like left or right in two identical corridors—these are neither in your control nor the players’.
Multi-function encounters
Encounters can of course serve more than one purpose, and often should. An encounter that purely drains the PCs’ resources or provides a fight in the middle of a long quiet spell might start to feel like padding if it is completely unrelated to the plot, atmosphere or theme. Your adventures will feel tighter and more story-driven if encounters contribute in these ways as well.
You might want the feeling that the world is big and busy and the PCs aren’t actually at the centre of it. In this case, some non-plot encounters can help. But you can still make them scene-setting, showing the world to the PCs, as well as providing the balance of combat and roleplaying that you want in your session.
What about you?
Although it is sometimes left out of GM advice on encounters, I don’t think this is really a new idea. Have you been using a similar concept already? Or has this article prompted you to start using portable encounters? Let us know your experiences and thoughts in the comments.