Designing encounters in Dungeons and Dragons used to be easy. First level of the dungeon? That’ll be level one monsters then! Giant rats, kobolds, skeletons, or similar. Level 2? That’ll be green slime and ghouls. What joyous simplicity.
In designing adventures for D&D, I have never had much time for the encounter design rules. The math involved simply drains me of all creativity and makes me feel straitjacketed.
To be fair, the rules themselves are not too bad. Third Edition (3E) uses the concept of ‘challenge ratings’ (CRs), and every monster is assigned a CR. A CR6 monster is considered a standard encounter for four 6th level characters. A table modifies this to take account of multiple monsters or multiple types.
Fourth Edition (4E) takes encounters as the primary building block of the game. It provides a huge amount of advice on building interesting encounters with unusual terrain or other effects, and a mix of monsters occupying different roles (artillery, skirmishers etc). 4E introduces the concept of the Experience Point (XP) budget. A standard encounter for four 6th level characters would have an XP budget of 1000 XP. These could then be spent buying the monsters for the encounter. 4E simply referred to the ‘level’ of the monsters, but this was mechanically similar to CR, and provided a guide to which monsters were appropriate for a party of a particular level. The 4E system had the advantage of greater flexibility than that of 3E. It allowed DMs to spend the budget on minions, elites as well as extra monsters or even traps.
Fifth Edition (5E) uses the same ‘XP budget’ system as 3E, and here a ‘medium’ encounter for four 6th level characters has a XP budget of 2400 XP. Modifiers are provided for multiple critters. It also makes use of the CR system as a supplementary guide as to what monsters are appropriate for particular parties.
First Edition (1E) and Second Edition (2E) did not, so far as I am aware, have mechanical encounter building rules like these. In the old days, the accepted rule of dungeon design was that the level of the dungeon roughly indicated the level of the creatures present. First level meant first level critters, and a small chance of a second or third level critter.
In early editions, monsters had a suggested ‘number appearing’, which was linked to meeting them on the dungeon level appropriate to their level. If they were encountered on deeper dungeon levels, then more would be encountered.
The “number appearing” was also used as a figure for estimating the numbers encountered in the wilderness, which was a feature of the procedurally generated hexcrawling supported by early editions, and had strong links to the war gaming roots of the game (More on that another time.)
So, what’s the problem?
First, as mentioned above, I find all of the 3E onwards systems of encounter design dull and a distraction from the creative exercise of writing an adventure. Actually having to sit with my budget on a bit of paper and trawl through monster books seeing which ones I’m ‘allowed’ to use is not my idea of fun or creativity.
Second, these systems rely on one critical fact: that monster XP awards and CRs are accurate. Given how many variables there can be in relation to a monster and encounter, I am very sceptical about the reliability of these scores, or what they offer beyond simply eyeballing the monster stats.
For example, in 5E, a medium encounter for 4 6th level characters would have a budget of 2400 XP. Compare an encounter between 1 wyvern (CR6, 2300 XP) and 6 harpies (at CR1 and 200 XP each, with a x 2 multiplier for six monsters = 2400 XP). A wyvern is tough, but a party could handle one as long as the healing kept coming. By contrast, 6 harpies are able to attack each individual party member with 6 charm attacks per round. They can do this from an altitude of 300 feet, which is out of range of most spells. You can argue this how you like, but I don’t find the idea that these encounters are of equivalent difficulty plausible. How do we even compare them?
So the budgetary systems are crude abstractions, and therefore I’m arguing that they are not worth the candle. I can see that some people find them helpful, and god knows D&D has a rule for virtually everything if you want it.
So should we go back to the old days? I’m attracted to the simplicity of saying that level one of the dungeon is where the CR1 critters live. But do we even write adventures that way anymore? Not so much.
So how should people balance encounters?
This question of course assumes that encounters have to be balanced. Fundamentally there is a clash of two different philosophies here. In OE, 1E and 2E the guidance on encounter design was more naturalistic (in that the number of monsters appearing were based on chance, or what “happens” to be there), but also simultaneously gamist (in that the level of the dungeon dictated the dangerousness of the creatures living there).
In 3E onwards, the system is purely gamist and teleological, in that the creatures encountered are based on the level of the party that turns up.
My preference is for a mix of the two. I want the game world to make sense, but I know that the point of the game is fun, and overwhelming the party isn’t fun. But striking that balance means following my gut and experience rather than spending a budget.