Ever had a session where the terrifying, legendary dragon just... sat there? It breathed fire once, took a few hits, and then bit the fighter until it died. It’s a common letdown. Honestly, it's the dirty little secret of many Dungeon Masters. We spend hours world-building, but when the initiative is rolled, we play the enemies like bags of hit points. This is exactly why Keith Ammann’s work, The Monsters Know What They’re Doing, became a legitimate phenomenon in the tabletop RPG community.
He didn't just write a blog. He basically started a movement that killed the "static bag of HP" trope.
The core premise is deceptively simple: every creature in the Monster Manual has a survival instinct. They have goals. A goblin isn't a suicidal zealot; it’s a cowardly ambush predator. If you understand the stat block, you understand the psychology. It sounds like common sense, but before Ammann started deconstructing the Fifth Edition (5E) mechanics, most of us were just eyeballing it.
The Logic Behind the Stat Block
When you look at a creature’s stats, you aren't just looking at numbers for math's sake. You're looking at their personality. Ammann argues that a creature with high Intelligence but low Strength will never, ever stand in the middle of a room and trade blows. It’s going to use cover. It’s going to use Misty Step. It’s going to run away the second things look south.
Take the Hobgoblin. In the standard Monster Manual, they have a feature called Martial Advantage. It gives them extra damage if an ally is within five feet of the target. This isn't just a "buff." It tells you exactly how they fight: they are Roman-style legionnaires. They fight in ranks. They don't break formation. If a player pulls one Hobgoblin away from the pack, that Hobgoblin’s entire tactical priority shifts from "attack" to "rejoin the line."
Most DMs miss this. They just see "extra 2d6 damage" and move on. But The Monsters Know What They’re Doing forces you to look at the Ability Scores first.
- Strength vs. Dexterity: Does the monster shove or dodge?
- Intelligence: Does it use complex traps or just bite the nearest thing?
- Wisdom: Does it know when it’s losing? This is the big one.
A creature with a Wisdom of 10 or higher generally understands self-preservation. A beast with Wisdom 7 might fight to the death because it's too stubborn or hungry to realize it's outmatched. Understanding this distinction changes the stakes of an encounter from a math problem to a narrative event.
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Why We Play Monsters "Wrong"
We’re lazy. Sorta. Being a DM is exhausting. You’re tracking HP, initiative, spell slots, and whether or not the Rogue is trying to steal the Paladin’s gold again. In the heat of the moment, it’s easier to just say "the Ogre swings his club" than to think about the Ogre’s fear of fire or its tactical preference for squishy wizards.
There's also a weird psychological pressure to let the players win. We want them to feel like heroes. But if the monsters don't try to win, the victory feels hollow. Players are smart. If they realize the dragon is ignoring the unconscious cleric to bite the 200-HP Barbarian, the tension evaporates.
Ammann’s analysis of the Beholder is perhaps the best example of this. Beholders are xenophobic, paranoid geniuses. They have a central eye that suppresses magic. If a DM just lets the party surround a Beholder, they’ve failed the lore. A Beholder would have a lair designed specifically to negate the party’s strengths—vertical shafts, anti-magic zones, and escape tunnels that only a floating orb can use.
When The Monsters Know What They’re Doing is applied, the game becomes harder, sure. But it also becomes more consistent. The world feels alive because the inhabitants aren't waiting for the players to show up so they can die.
The Action Economy and Survival
The "Action Economy" is a term you'll hear a lot in D&D circles. It basically means the side with more actions usually wins.
Most monsters are outnumbered by the party. To compensate, Ammann highlights that monsters must use their actions efficiently. A wolf doesn't just bite; it uses the Help action or the Pack Tactics feature to ensure its friends hit. It drags prey away from the group. It targets the weak.
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This leads to a controversial topic: targeting downed players. In a "friendly" game, a DM might ignore a player who is at 0 HP. But an intelligent enemy—like a Drow Assassin or a Lich—knows that the Cleric can bring that fighter back next turn. They know they need to "double-tap." It’s brutal. It’s "mean." But it’s what the monster would actually do.
The Evolution of the Blog to the Book
What started as a niche blog grew into a series of books published by Saga Press. It’s rare for a fan-made tactical guide to get that kind of mainstream publishing traction. It happened because there was a massive vacuum in the 5E ruleset. The Dungeon Master’s Guide tells you how to build a world, but it doesn't really tell you how to run a combat that feels like a tactical thriller.
Ammann filled that gap by treating the Monster Manual like a field guide. He uses a specific methodology:
- Examine the stats.
- Analyze the features.
- Determine the "Combat Heuristic" (the flowchart of decisions).
- Define the "Morale Threshold" (when does it run?).
This last point, morale, is something D&D dropped in later editions, but it’s vital. In older versions of the game, there were literal dice rolls to see if monsters fled. Now, it’s up to the DM. By using the "The Monsters Know What They’re Doing" logic, you decide beforehand. A group of bandits will probably flee if their captain falls. A mindless zombie will never flee. This makes the world feel grounded in reality rather than just being a series of combat encounters.
It's Not Just for "Hardcore" DMs
Some people worry that using these tactics makes the game "DM vs. Players." That's a valid concern if you're a jerk about it. But if you're transparent, it actually empowers players. When players realize the monsters are predictable based on their nature, they start using tactics themselves. They start scouting. They start using Silence to stop a caster because they know that caster is going to try to teleport away.
It turns D&D into a game of chess instead of a game of "I hit it with my axe."
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Practical Examples of Tactics
Consider the Gelatinous Cube. It’s slow. It’s brainless. How does it "know what it’s doing"? It doesn't "know" in a sentient sense, but it has an evolutionary niche. It’s a scavenger. It stays in narrow corridors where it can't be bypassed. It doesn't chase; it waits. If a DM puts a Gelatinous Cube in an open field, they aren't playing it right. It belongs in a 10-foot-wide hallway where it is literally unavoidable.
Then there are the Dragons. A dragon in its lair is a god. It has legendary actions. It has lair actions. A dragon that stays on the ground is a dead dragon. An intelligent dragon will fly, use its breath weapon, and stay out of range until the breath weapon recharges. It will use its tail to knock people away. It will use its wings to create dust clouds.
If your players complain that the dragon is "cheating" by flying away, they aren't upset with you—they're upset that they haven't figured out a way to ground it. That’s a good thing! It’s a challenge they have to solve.
Actionable Steps for Your Next Session
If you want to start implementing these ideas without reading the entire 400-page book tonight, start small. You don't need to be a grandmaster strategist to make your encounters better.
- Read the features out loud. Before the session, look at the monster’s special abilities. If it has "Nimble Escape," it should be Disengaging or Hiding every single turn. No exceptions.
- Set a "Flee Point." Pick a percentage of HP or a specific event (like the leader dying). When that happens, the monsters stop fighting. They run. They beg for mercy. They vanish into the shadows.
- Look at the environment. Monsters live there; players are just visiting. The monsters should know where the traps are, where the cover is, and where the narrowest bottlenecks are located.
- Target the right people. An animal attacks the biggest threat or the easiest meal. A soldier attacks the person wearing a dress and holding a staff (the wizard). A rogue monster attacks the person who is already wounded.
- Narrate the tactics. Don't just say "the goblin hides." Say, "The goblin, realizing you're much stronger than him, scurries behind the crates and disappears from view, giggling nervously."
The shift in table energy is almost immediate. Combat stops being a chore and starts being a story. Your players will start taking the world more seriously because the world—specifically the monsters in it—is finally taking them seriously.
Ultimately, Keith Ammann gave us permission to be "effective" villains. Not because we want to kill the characters, but because the story deserves enemies that feel like they actually want to survive. When the monsters know what they’re doing, the heroes have to be even better to win. That’s where the real magic of the game happens.