I'd like to see your process of building an encounter. How do you go about designing the area the fight may or may not take place in? You take your players' expectations and what they wanna fight into consideration, naturally, but other than calculating out CR for the encounter, do you do anything worth mentioning when deciding if they're fighting 20 Kobolds and their Half-Dragon Leader, or 10 Kobolds and 2 Half-Dragons?
One of the good things about encounter design is that there's no real way to do it wrong. Some encounters are better than others, sure, but no encounter is wrong. If you get nothing else from this essay, at least take solace in that, even when it might feel like it, you can't actually be doing anything the wrong way.
Now, as for my personal approach, it more or less all boils down to the experience I want to convey. So the short answer to this question would be, "Whatever works best with the experience you want to build."
Obviously, that answer by itself isn't very helpful, so please allow me the chance to explain at great -- possibly unnecessary -- length.
For the example given, Before I even tried to answer the question, without even realizing what I was subconsciously doing, I asked Andreas about the circumstances of the encounter, because I needed to know more about its context, since to me, that's just as important to the design as the combatants involved or the battlefield they'll be fighting on.
When asked for details, Andreas replied:
The party's out hunting for red feathers to help complete a Roc Summoning ritual, they're intent on summoning it to drive off the Dragon that's been harrassing the city for months. But, the Dragon has patrols out to stop any good-doers. Out in the forest, we find our heroes, surrounded ...
So now I know what's going on outside of and leading up to the encounter. Now I can start setting it up.
The first thing I will do is take mental stock of the important details, then imagine the most likely circumstances under which the encounter will take place:
- The players are trying to complete an objective (collect red feathers) that doesn't directly involve the main enemy (the dragon).
- Ideally, the party doesn't want to be found out while they're doing this.
- The main danger is the patrols sent out by the dragon, made up mostly of kobolds, led by a few half-dragons.
- Collecting feathers may or may not also be dangerous (depends on what kind of feathers)
- The battle(s) will most likely take place in the forest, or wherever the party will be looking for their objective (the red feathers)
So from here, I know that the encounter or encounters are most likely going to be taking place as the patrols stumble upon the adventurers while they search for these feathers, and this gives me the idea for the most important concept to my design: the feeling I want the experience to convey.
What I mean by this is essentially how I'd want the players to describe the experience using only a single sentence. And in this case, I think that sentence would be something like:
The party tries to remain unseen by the patrols as they dodge through the woods, searching for their elusive objective, every noise leading their pursuers a little closer.
I put the words above in bold, and separated out that particular sentence because of just how important this is to my process. This is the Armature, the single thing upon which everything else will be attached. Now that I have this, I have the essence of the encounter: I have my goal as the GM. Every single element I add from here on out should be building around the armature, and should bring the entire experience closer to that ideal. If it doesn't, I need to either think of a way to change that element so that it does, or consider cutting it out entirely.
Now that I know my objective, I think about what I can do to make that objective a reality. I usually start with the backdrop for the encounter -- the setting, the weather, the time of day, etc. -- because it will set the tone for everything else I add later.
I ask myself what kind of backdrop lends itself well to the experience I'm trying to build. Since I know that the party will be in the forest, and I imagine that they will likely be trying to avoid these patrols, I figure a densely wooded setting with plenty of thick patches of undergrowth would be ideal: the trees will provide shadows and a place to search for the feathers, while the patchy undergrowth provides good -- but not perfect -- cover for the party, so they'll still have to dodge from cover to cover while they search.
As for the weather and time of day, I would think that nighttime and/or obscuring weather would make this easier, but whether or not that's a good thing would likely depend on the group. What's more, the group should have some agency here as well, specifically the ability to choose the time of day that they'll begin this operation.
Since niether of these choices are particularly important to the armature itself (though they can greatly change the difficulty of the experience), I'll let them go; I can easily just let the group decide when to go, and if I feel like they're having too easy or too tough of a time, I can change the weather through GM fiat. And that should be all I need for setting.
I can almost completely visualize the encounter now; the party is darting from bush to bush, dodging patrols, either in the dead of night or in the bright of day, while seeking out these feathers they need to defeat the evil dragon.
So now I can decide how this actually works. Granted, I could plan out how this encounter should go down to a T, but I know how players work when given an encounter setup: which is to say, I know that they often don't.
Because of this, outside of the most basic circumstances, I usually plan out as little as possible to make the encounter work the way I want it -- less really is more. Having said that, I prepare to be unprepared: I make a mental note of as many off-the-wall scenarios that might come up as I can, and I try to think of a general idea of what I might be able to do if it comes to pass. This way, I'm at least not completely caught off-guard the first time something goes astray.
So for this encounter, I remember my armature and the mechanics mostly write themselves. The main conflict here is the party being found by the patrols while they're searching for these feathers, so it's easy enough to create the basics from that:
- Assuming they want to, the party can begin the operation hidden from the enemy (they could always just go in guns blazing if they wanted -- and if that's their choice, that's okay -- give 'em a fight to remember!)
- The party makes stealth checks as they move from cover to cover, getting serious bonuses against low DCs as long as they remain behind cover and out of earshot of the moving patrols.
- Party members can make Investigation/Perception checks to try and find the feathers they need (the actual details of these feathers aren't super-important; use whatever's convenient and fits the story)
- If the party is discovered, they must fight the patrol, and risk attracting more.
The only other things I may need to determine are the details as to the manner in which more patrols are added to the encounter if the party's discovered, but this can be improvised pretty easily, or a simple noise/attraction mechanic can be developed:
- Once a party member is discovered, the discoverer calls out to the rest of the patrol; combat ensues
- The louder the combat, the higher the chances that another patrol comes to investigate the noise (simple d20 roll, modified by my opinion of how loud this situation is, against a DC proportional to how close other patrols might be)
- Each successive patrol has a higher chance of containing more difficult enemies, including more leaders or other tricks, perhaps topping out at attracting the dragon itself!
- Once a patrol is dispatched, the party can run and hide again before anyone else shows up, returning to the status quo.
Once again, the actual specifics of these mechanics -- modifiers and DCs of the attraction rolls -- aren't terribly important; just be aware of how different comparative numbers will affect the probabilities, and I can tailor the rates to my liking.
And with that, I can finally get to addressing the original question...
What monsters do we include?
Well, by this point, most of the work is already done! I know that the enemies will be in patrols of increasing difficulty, and that they will be comprised mostly of kobolds and half-dragons. Following this, it makes sense to have smaller patrols of mostly, if not entirely kobolds at first, and then when/if more patrols are attracted, they may be led by a half dragon, or even two, in addition to an increasing number of kobolds.
Seems almost anti-climactic to have the answer be so brief after such a long build-up, right? That's why I do it this way: I let the experience I want inform the elements of the encounter. Doing it this way, by the time it gets to where I'd be choosing monsters, the choices are usually all pretty clear.
I hope that in addition to a little insight into how I design encounters, that this will also help de-mystify the process, as well as demonstrate how simple and how loose DMing really can be while still making awesome encounters. I would want people to take away from this that the expert encounters aren't the ones that are orchestrated down to every round; they're the ones that allow the party room to breathe and do what they do. Characters are what make the game awesome, not fights. So in everything you do as a GM, let your characters be awesome, and they will do most of the work toward making the game great! :D