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Game Masters' GuideRunning the GameEncounters

Encounter Composition

In this section we'll talk about how to assess the challenge NPCs in an encounter pose to the party, based on their level vs. the PCs' levels.

On Encounter Balance

Remember that the levels of NPCs or PCs aren't a particularly strong indicator of the characters' competence, because in OSR+ each level confers a single perk to the character, as opposed to a plethora of new abilities. While higher-level characters are more likely to succeed in their actions because they're more likely to have a few more points in their attributes than lower-level characters, they still deal the same amount of damage on average (because the damage weapons deal is fixed) and have similar AP and HP.

Prioritize Context in Encounter Design

In OSR+ prioritizing the context of an encounter means privileging the integrity of the fiction over its gamist aspects. Put simply: if the PCs wander into a cave that is home to an ancient dragon, that dragon's stats do not scale with the stats of the PCs. Similarly, if the PCs come to blows with the king's elite guard, you should arm the guard with the gear and experience befitting a king's elite guard, even if that means the PCs won't stand a chance against them. Mechanically, the system supports you on this decision. Which leads us to...

Never Underestimate the PCs

In OSR+, the PCs are very powerful: they're generally as powerful at first level as they're going to be for the rest of the game. From a design perspective, this is because we want the PCs to be heroes out the gate, so the system doesn't gatekeep their abilities behind levels. Add to this that it is relatively easy (numbers-wise) to stabilize PCs who are on death's door, and barring fatal perils, PCs can't get instantly killed from any single source of damage in the game. Finally, PCs have a wealth of narrative "outs" to protect themselves from sticky situations, from story tags to fate points.

An Encounter is a Fight, Not a Game

As noted above, when you design encounters, you shouldn't be thinking of them as random battles in a video game that exist purely to level up the party. Gaining a level, regardless of the advancement method you choose, requires advancing the narrative, and so a narratively meaningless fight (no matter how difficult it may be mechanically) can't do that. If an encounter doesn't have any impact on the narrative, then you should question why you're running it at all.

Assessing the Challenge

Because NPCs aren't fully fleshed out like PCs—they don't have story tags, fate points, or the opportunity to stabilize via death's door mechanics—any individual NPC tends to be weaker than any individual PC. And because we want to keep the number of turns available to the GM equal to the number of turns that the PCs have, we have to distribute complex NPC strategies across the whole NPC party.

Calculating NPC Party Level

Selecting the right number of NPCs for the encounter is tricky. We don't want the PCs sitting around forever while you roll for all the NPCs, so try to keep the number of actions the NPCs have equivalent to that of the PCs, excluding the legendary actions that BBEGs may have, and NPCs that have bonus actions which can be used as attacks. It’s always better to add more minions to a single mob (thereby increasing their chance to hit) than it is to add more NPCs with their own unique actions to the mix.

Finally, a good rule of thumb is that the combined total levels of the NPCs in the encounter should be 3 times the combined total level of the PCs’ levels. That is, if you have four PCs at 2nd level, that’s 8 combined levels, so you should bring 24 levels of NPCs to the encounter. For example: 

  • An 8th level boss (+8);
  • A 5th level special (+5);
  • A 5th level special (+5);
  • 1 mob composed of three 1st level minions (+3);
  • 1 mob composed of three 1st level minions (+3);

This NPC party will thus have 5 actions per round: the 8th level boss, the two 5th level specials, and one action for each of the 1st level mobs.

Higher Level Play

The numbers suggested above may get out of hand as your PCs approach higher levels. Generally, you're good up until you get past 5th level. For example, a party of four 5th level PCs would need 60 combined levels in the enemy party:

  • Two 9th level bosses (+18);
  • Three 5th level specials (+15);
  • 1 mob composed of three 3rd level minions (+9);
  • 1 mob composed of three 3rd level minions (+9);
  • 1 mob composed of three 3rd level minions (+9);

The makeup of this encounter is probably still reasonable, given that we're still dealing with 5 actions on the GM-side. However, once we start dealing with PC parties that exceed 5th level, it doesn't make sense to keep packing on the levels. Instead, consider adding environmental hazards, escalations, and twists to the mix to use up the remaining levels.


An environmental hazard might include treacherous footing like lava pits, bad weather conditions, or even living perils like poisonous plantlife in the area. These hazards can affect both the PCs and the enemy NPCs, but it's likely the enemy NPCs are prepared for their fighting conditions.


Escalations mean things get worse for the PCs over time. Imagine the PCs find themselves in a trash compactor facing off with tentacled monstrosities. Perhaps in round 1, the walls close in, forcing everyone to fight the monsters in close proximity. In round 2, hatchlings burst from large eggs on the monsters' bodies, which doubles the number of minions the PCs face. These escalations change the stakes of the encounter, thus they should be more expensive in your calculus.

tWISTS (+20)

Finally, you can introduce a twist that turns the tables on the PCs. Perhaps someone in their party is actually a traitor, or the magical artifact they came to steal has a mind of its own and has now turned against them. Twists should force the PCs to change their entire strategy in order to survive the encounter.

With these perils as options, consider a party of four 10th level PCs. According to our calculus, you'll need to bring 120 levels of NPCs to the encounter:

  • One BBEG, who's been perked to 15th level (+15);
  • Two 6th level specials (+12);
  • 1 mob composed of five 4th level minions (+20);
  • 1 mob composed of five 4th level minions (+20);
  • 1 mob composed of five 4th level minions (+20);

With this setup, you still only need to manage 5 actions, and you have 33 levels leftover to redistribute into the encounter. With what remains, you might add a twist for 20, and maybe a couple environmental hazards to keep things interesting. That leaves you with 3 levels on the table, which you could either disregard or sprinkle back into your NPCs as additional perks or abilities.

Types of NPCs

When you construct an encounter, each NPC fills a role as either a minion, special, boss, or BBEG in the NPC party. These roles help define the behavior, power, and utility of each NPC so that we can have the NPC party behave strategically as a group.


Minions are meant to be cannon fodder for the encounter; they’re usually the same level or lower than the PCs, and outnumber the PCs many-to-1. They go down in a single hit regardless of damage, depending on the desired cinematic effect. When stating them up, ignore wounds, HP, AP, soak, etc. They die at 0 HP unless stabilized on the round after they reach 0.


Specials are NPCs who are fewer in number in an encounter, but only a few levels above the PCs' level. Stylistically, a special is meant to be very good at one thing, so all the choices you make to build them should serve that purpose. They are very likely to use the key ability they're designed around as often as possible, and you can bolster that ability with a relevant stance. Specials also ignore wounds and go down at 0 HP like minions.


A boss is usually one-of-a-kind and the strongest NPC in the encounter. They should be at least as powerful as the combined levels of the party (so a 4th level party affords a 4th level boss and an 8th level party affords an 8th level boss). Bosses behave more strategically than their allies; they're more likely to use weapon tactics, defensive actions, and the environment against the PCs. You can also give a boss a few stances relevant to its role in the encounter to make it more challenging, and all deeds (if it's a martial). You can decide whether your boss goes down at 0 or uses wounds, but generally stick to 0 if a BBEG is also present.


A “big bad evil guy” is usually the adventure's main villain, much more powerful than a boss. BBEGs are meant to be a recurring element throughout the adventure, so you shouldn’t throw a BBEG at the PCs directly, unless you’re prepared for them to die accidentally. BBEGs are constructed in the same way as a PC and have additional perks, stances, and deeds that go above and beyond other NPCs. They have wounds and experience death’s door like PCs.

Building BBEGs

When you make a BBEG, you want to make a full character sheet. A BBEG has access to all the mechanics that a PC does, full stop. You can still write down the BBEG's stats in NPC shorthand, but BBEGs can do all the things PCs do, and more.

BBEGs are High Level

BBEGs are always significantly more powerful than the PCs, usually having twice as many levels as the combined party. A campaign BBEG can be pinned at 10th level and then earn perks above 10th for every level the PCs gain thereafter. (But do not give them attribute perks beyond level 10.)

BBEGs Come Prepared

BBEGs always come prepared to throw down. They enter play with all the spells, defenses, or other magic items they may possess readied or cast.

BBEGs are Resourceful

BBEGs have magic items, expensive armors, and their choice of weaponry. These things may give them other activated or passive abilities. Money is no object for a BBEG. In the same vein, BBEGs don't run out of MP or whatever resource they need to carry on in the encounter exactly because they come prepared.

BBEGs Have Legendary Actions

Legendary actions are a concept borrowed from the World's Most Popular RPG: special abilities unique to them that affect the entire encounter. Each legendary action may trigger once per encounter, in addition to any actions the BBEG takes on his turn. So for example, on round 1 the BBEG might cast Enervate on a PC and use his legendary action to raise a bunch of zombies to his command. A legendary action doesn’t need to be a specific ability the BBEG has; it can be as broad as "reinforcements arrive" or "the BBEG hops into Clockwerk mech," for example.

BBEGs Break Rules

You can give BBEGs more than 1 action per turn, even if their kit or class would not allow it. Calculate these extra actions as perks. This may mean attacking twice and still being able to parry, or casting two spells on a single turn. Don't be afraid to give them stuff the core rules says they can't have, because their edge can be justified by the vast resources they have at their disposal. The only caveat here is to make those decisions when you build the BBEG, not when you run him.

BBEGs Use Stances

Give BBEGs all 10 stances, but be honest about what they would have picked as real, well-rounded villains. That is, if you're building an evil cleric who fell out of favor with their church, it might make sense for her to have taken Occult Knowledge and Ritual of Prophecy, even though those stances do not have any effect on combat encounters.

BBEGs Have Legendary Resistance

Also borrowed from the World's Most Popular RPG: BBEGs are immune to spells or other effects that would incapacitate, stun, mind-control, charm, or otherwise prevent them from acting, unless the PCs expend a lot of narrative resources to pull it off (e.g., fate points). Similarly, BBEGs are immune to dying from called shots or fatal perils that would normally off other NPCs. How you justify this from the fiction has to make sense, and you have to reward the PC for making the attempt if they're successful.

For example, if a PC declares a called shot on the BBEG with an arrow to the throat, the arrow might hit and deal more harm than expected (perhaps the BBEG catches it before it plunges all the way through) or perhaps the attack stuns the BBEG for a turn where that would otherwise be impossible due to their legendary resistance.

BBEGS Explode Dice & Use Fate Points

BBEGs have the same capabilities as PCs, which means they have fate points and story tags, and explode dice when they roll a 6. Keep track of the BBEGs' fate points throughout the adventure, as they do not recover.

Encounter Etiquette

While you want to keep in mind that a fight is a fight, not a game, you also want to be a fan of your players. This doesn’t mean you have to baby your PCs. The end goal for the GM is to create a cinematic experience that respects the fiction, which requires that PCs feel threatened enough that they will engage against the NPCs heroically.

Here are some things you should avoid doing when running an encounter:

  • Called Shots. NPCs generally don’t make called shots against PCs, unless there’s a specific cinematic reason for them to do so. (BBEGs are an exception.)
  • Incapacitating Abilities. Try to avoid having the NPCs use abilities that take PCs out of the fight for more than a single round. Obviously, this eliminates a broad swath of spells and abilities used across many kits and classes. The reason to avoid abilities that take players out of the action is exactly that: it's no fun for players to sit on the sidelines doing nothing. Instead, use incapacitating abilities on the NPCs in the PCs' party.
  • Defensive Action, Tactics. BBEGs and bosses are especially tactical and make use of defensive actions, stances, and weapon tactics (including rarely used maneuvers like shield sacrifice), but your average NPC doesn't, except in the case of a special using a defensive action or tactic that is part of their concept. This is because the spotlight should always be on your PCs, not on the cool stuff your NPCs can do.
  • Fate Points & Narrative Mechanics. Non-BBEG NPCs don’t have fate points or story tags. They can't take action to affect the narrative and when you run them, and you always want to make decisions for them from the perspective of the fiction and not the narrative.

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