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Choose Monsters Based on the Story

by Mike on 31 May 2021

Here's a one-line encounter building rule for you:

Choose the number and type of monsters that make sense for the story, the situation, and the world.

Many DMs build encounters by looking at the characters, their levels, and their overall power and then select monsters to challenge those characters. I argue this takes things backwards. The world doesn't conform to the level of the characters. The world is the world and it has exactly as many monsters of various types as it is supposed to, including monsters far weaker than the characters and a few far stronger.

This idea joins two other topics together: building situations and the lazy encounter benchmark. If you haven't read those articles, you may want to when you're done with this one.

Instead of balancing combat encounters around the characters, focus instead on running adventures appropriate for the station and power of those characters. We've talked about this before in tier-appropriate adventure locations. 1st level characters shouldn't likely be knocking on the door of a fire giant citadel and 18th level characters aren't likely hired to clean out a warren of kobolds. The quests fit the characters. The world does not.

Once the characters choose a quest appropriate to their capabilities, let go of worrying about encounter balance and instead focus on what makes sense for the location.

What would that location look like if the characters never showed up?

There's some diametrical thinking with D&D around this idea. When we're preparing our games we put the characters first in our mind. This is step one of the eight steps from Return of the Lazy Dungeon Master — intended to put the characters into our minds as we build out the rest of our adventure.

However, we also want to let go of the characters when we're filling out a location full of monsters. The lair is the lair regardless of the characters. How does it work on its own?

Too often DMs focus on how powerful the characters are and ignore everything else. When we review the characters, we're looking for backstories, hooks, plots, and desires we can tie into our adventure — not whether a character is level 8 with great weapon master. Many DMs ignore the backstory and focus on developing carefully calculated encounters for each room in a dungeon intended to challenge the party. Instead, focus on the story for both the characters and the monsters they might face.

Upward and Downward Beats with a Loose List of Inhabitants

In step seven of the eight steps (Chapter 9 in Return of the Lazy Dungeon Master), we list the monsters that might show up in our session. There's a reason we don't tie monsters to locations most of the time. The situation is dynamic. It can change based on what's happening in the world and how the pacing of our game feels. Have the characters had a lot of great luck sneaking around the hobgoblin fortress? Maybe the next room is filled with veterans practicing their phalanx maneuvers. Have the characters been having a hard go of it with a lot of bad rolls? Maybe they find two hobgoblins passed out over a table full of cards. The situation is dynamic in these locations and we can decide during the game what sort of pacing will be the most fun for the moment.

Is it Deadly?

The only time we need to worry about the difficulty of an encounter is if it might be inadvertently deadly. We can check this quickly with the following guideline:

An encounter may be deadly if the sum total of monster challenge levels is greater than one quarter of the sum total of character levels, or half of character levels if the characters are above 4th level.

This is close enough to the standard encounter building guidelines to serve us without needing an online tool or a bunch of reference tables. Of course, many factors change the difficulty of a battle beyond just level and challenge rating including the situation of the fight, environmental effects, magic items, player skill, character synergy, and others; but the benchmark is still a handy gauge to let you know if things are edging towards deadly. This is a loose guideline, not a hard rule, intended to be used after you've already built the encounter from the situation in the world. No encounter building system is accurate anyway so this is as good as any.

If they are walking into a deadly encounter, warn them. Their characters can probably tell things are dire even if the players can't. Give them a fair warning that "this foe is beyond you" so they can make an informed choice.

Always Consider the Story

The urge to focus on mechanics is strong but it's the story that matters. Just as our D&D games start and end in the fiction, so should our prep. What's happening in the world? What makes sense? What creatures would be lurking around here? Think about things from inside the world first and then examine the mechanics to bring it alive at the table.