Introduction
Monster Core 2 reinforces one of PF2e's best GM tools: group enemies that do not require twenty separate turns. Troops and swarms let one monster entry create crowded battlefield pressure, and garrison scenes extend the same idea to a whole defended location.
They work best when the group has a battlefield job and when the party can change the scene by breaking, bypassing, rallying, frightening, or outmaneuvering it. A troop is not interesting because its stat block has a special format. It is interesting because it changes space, morale, objectives, and target priorities.
Use this guide with Monster Core 2, Monster Core guides, Battlecry, skirmish warfare, battle magic, encounter use, war campaigns, and encounter building.
Copyright-Safe Scope
This guide is original table advice for using troops, swarms, and garrisons. It explains encounter roles, player counterplay, GM procedure, tuning, and campaign uses. It does not reproduce complete troop or swarm rules, stat blocks, exact ability text, skirmish procedures, or copied creature entries from Monster Core 2, Monster Core, or Battlecry.
That matters because group-threat rules are easy to over-explain and harder to run well. Keep the book open for exact mechanics. Use this guide to decide why the group threat is in the scene.
Troops
Monster Core 2's troop rules describe an organized group as one monster spread across four segments on the grid. Each segment is 10 feet on a side and only as tall as the creatures that make it up, and segments have to stay contiguous: every segment must share at least 5 feet of an edge with another one, so a diagonal touch does not count. You measure flanking, cover, and similar geometry from the center of whichever segment matters.
A troop carries two Hit Point thresholds, typically at two-thirds and one-third of its maximum. Dropping below the higher one removes a segment and leaves three, dropping below the lower one leaves two, and at 0 Hit Points the troop disperses entirely, with the survivors surrendering, fleeing, or being mopped up as the GM decides. Whoever knocked the troop past a threshold usually picks which segment goes, which is a small but excellent tactical lever: you get to decide whether the line thins at the gate or at the flank.
| Troop feature | Table impact |
|---|---|
| Segments | The troop occupies real battlefield space and has to keep that space connected |
| Thresholds | Damage removes parts of the troop instead of only lowering a number |
| Area and splash weakness | Most troops are weak to both, so casters and alchemists get different priorities |
| Targeting rules | Single-target tricks do not automatically solve a crowd |
| Downtime recovery | Restoring lost segments takes long-term treatment of casualties or new recruits |
Monster Core 2 Troop Layer
Two details do most of the work at the table. First, troops are typically immune to non-damaging effects that target a single creature, so a charm spell or an ordinary Demoralize bounces. Reach is what matters instead: an ability that can target 5 or more creatures affects one segment, 10 or more affects two, and 20 or more affects the whole troop. Anything that affects all creatures in an area hits every segment in range, rolling separately for each. A non-damaging effect that would stop a segment from acting or drive it off removes that segment outright and drops the troop to its next threshold.
Second, troop movement is deliberately loose. You move one segment and the others follow, then arrange them however you like as long as none of them travelled farther than the segment you moved. If you would rather not move at all, you can reshape the whole formation in place as long as one segment stays put. That is how a troop funnels into a corridor, spreads across a courtyard, or peels off a flank without becoming a positioning puzzle for the GM.
One more constraint worth remembering before a player asks: troops consist of multiple discrete creatures, so they cannot be summoned.
Swarms
Swarms are not organized soldiers. They are a moving mass, and Monster Core treats the swarm's size entry as the size of the whole cloud even though its component creatures are usually Tiny. A swarm can occupy the same space as other creatures, and it has to be in that space to use its damaging action, which is why backing away is a tactic rather than cowardice.
Swarms are immune to grabbed, prone, and restrained, and swarm mind makes them immune to mental effects that target only a specific number of creatures while leaving them open to mental effects that cover an area. They typically carry a weakness to damage dealt over an area, which is the whole reason the party's area spells and splash weapons suddenly look like the correct answer.
| Swarm use | Why it works |
|---|---|
| Infestation | Makes the environment feel dangerous |
| Ambush | Forces fast reaction and movement |
| Attrition | Punishes lingering in the wrong space |
| Horror | Makes the enemy feel hard to reason with |
Troops Versus Swarms
Troops and swarms both simplify groups, but they should feel different at the table. GMs also reach for two other group shapes constantly.
| Group type | Table identity | Best counterplay |
|---|---|---|
| Troop | Trained or purposeful group with formation, morale, orders, and cohesion | Break command, use area pressure, exploit terrain, frighten, flank, or force movement |
| Swarm | Mass of small bodies acting through instinct or infestation | Area damage, splash, escape routes, containment, smoke, fire, water, or environment |
| Mob | Social crowd, riot, cult rush, or panic scene | Influence, intimidation, rescue, exits, visible leaders, and public stakes |
| Garrison | Defended location with troops, gates, reserves, alarms, and objectives | Recon, sabotage, negotiation, stealth, siege tools, or targeted assault |
Rules To Say Out Loud
Troops and swarms break player assumptions, so explain the visible fiction before relying on the mechanics.
| Rule-facing point | Table explanation |
|---|---|
| Troops are organized units | The party is fighting a coordinated formation, not one giant person |
| Troops shrink as they take damage | Damage represents casualties and broken cohesion, and crossing a threshold costs a segment |
| Swarms share space | A swarm moves into a creature's space, and it must be in that space to hurt anyone |
| Area and splash matter | Area effects and splash damage are usually better answers than single-target attacks |
| Single-target control does nothing | A charm, trip, or Demoralize aimed at one creature simply does not apply to a troop |
| Summoning limits apply | A troop is many creatures at once, so it cannot be summoned |
Troop And Garrison Jobs
Before you pick a stat block, pick the job. A group enemy with no job is just a large number.
| Job | Table effect |
|---|---|
| Hold ground | Makes movement, forced movement, and area effects matter |
| Screen leader | Protects a commander, caster, monster, or siege crew |
| Block retreat | Turns the encounter into a positioning problem |
| Pressure civilians | Creates rescue stakes and moral urgency |
| Guard equipment | Makes siege weapons, banners, gates, or vehicles into objectives |
| Show the war | Makes the battlefield feel bigger than the named villains |
Troop Use Rankings
| Troop use | Why |
|---|---|
| Guarding a gate, bridge, or chokepoint ● | The troop's space matters immediately, and melee characters get a real positioning problem. |
| Screening a commander, caster, or ritual ● | The troop creates target-priority pressure instead of being another bag of HP. |
| Garrison as location pressure ● | The fort, wall, barracks, or occupied district becomes the encounter. |
| Battlefield objective with civilians or supplies ● | Rescue, evacuation, and protection make non-damage turns matter. |
| War campaign recurring unit ● | Great when morale, reputation, replenishment, and terrain all matter between sessions. |
| Empty-room troop fight ● | It works mechanically, but it wastes the reason troops exist. |
| Too many troops at once ● | The scene becomes a map-clogging rules lecture instead of a battle. |
| Troop as disposable minions beside an already extreme boss ● | Too much action pressure turns the scene into a tax instead of a choice. |
A troop is not a shortcut for "I want twenty enemies." It is a shortcut for "I want the map to feel crowded without making initiative miserable." The best troop encounter is not "you fight forty guards." It is "the guards control the one thing you need before the bell rings."
Swarm Use Rankings
| Swarm use | Why |
|---|---|
| Infestation puzzle ● | The swarm is part of the environment, so movement, fire, smoke, water, doors, and containment matter. |
| Horror pressure ● | Swarms are excellent when the goal is panic, contamination, or "get out now." |
| Area-damage reward ● | Casters, alchemists, and splash users get to feel smart for bringing the right tools. |
| Swarm plus hazard ● | Strong if the hazard is readable and interactive, miserable if it is just hidden damage. |
| Single hallway attrition ● | It creates pressure, but it turns repetitive if the only answer is backing up. |
| Surprise swarm with no clues ● | Players need signs: buzzing, movement under doors, gnawed bodies, disturbed nests, or odd silence. |
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Battlecry Troop Rules To Remember
Battlecry's skirmish subsystem is where troops stop being monsters and start being units the party commands. Use it for a special session rather than a weekly habit; it changes what a war scene can be.
| Rule piece | Practical meaning |
|---|---|
| Troop as creature | A troop runs on one creature-style stat block, similar in table purpose to a swarm but representing organized combatants |
| Skirmish leadership | A PC establishes leadership over a troop, stands inside its space, and moves with it like a mount |
| Five actions | Each turn the leader splits five actions between themself and the troop, 3 and 2 or 2 and 3, and both regain a reaction |
| Rout checks | A troop rolls a Will save when it crosses a threshold or loses its leader, and a critical failure removes it from the battle |
| Leader presence | A led troop treats its rout result as one degree better, so losing the leader is a morale event, not just a lost turn |
| Skirmish bonds | A day of downtime training grants one special bond between a leader and a specific troop |
| Commander interaction | A commander can choose a troop as a squadmate and treat it as one ally for tactics |
| The Garrison chapter | Battlecry's troop stat blocks work as enemies, as PC-led allies, and as models for building your own |
Plan for two implications. Mindless formations such as zombies and clockwork constructs are immune to rout checks because a rout is an emotion, fear, and mental effect, which is exactly why undead and construct armies are the ones that hold a line forever. When a leader goes down, an ally can spend a two-action Diplomacy activity to take command mid-battle, which gives the party something better to do than watch a unit break.
Garrison Scene Templates
A garrison is not a bigger troop. It is a defended place, and the place is the encounter.
| Template | What the garrison does | Player choices |
|---|---|---|
| Break the gate | Holds a defensive line while engineers, casters, or siege gear work | Assault, infiltrate, sabotage, climb, negotiate, or create a diversion |
| Rescue under occupation | Controls streets, doors, and movement around civilians | Evacuate, split the troop, hide civilians, distract officers, or cut retreat |
| Siege engine guard | Protects a weapon, ritual platform, banner, or vehicle | Destroy the objective, steal it, disable it, or turn it around |
| Barracks alarm | Reinforces over time unless silenced | Sneak, delay, misdirect, barricade, or race the clock |
| Broken morale | Starts disciplined but can rout if leaders, banners, or supplies fall | Target morale, intimidate, expose lies, or show mercy |
| Last stand | Holds a position for duty, fear, oath, pay, or desperation | Negotiate, break formation, force movement, or survive until relief |
Use GM subsystems if the scene is bigger than one initiative track. A siege, infiltration, chase, reputation shift, or war objective often deserves structure beyond "roll attacks until quiet."
Encounter Templates
| Template | Group threat | How to run it |
|---|---|---|
| Hold the bridge | Troop | Put the objective beyond the troop and give both sides reasons to move. |
| Break the formation | Troop | Let Athletics, intimidation, area effects, flanking, and command disruption matter. |
| Burn the nest | Swarm | Give the party time pressure, safe zones, and equipment options before the swarm reaches them. |
| Escort through panic | Troop or swarm | Civilians, wagons, prisoners, or wounded allies make movement more important than DPR. |
| Ritual under siege | Troop | The troop buys time for a caster, commander, cultist, or siege engine. |
| Infested ruins | Swarm | The swarm is one part of a larger exploration problem with doors, smoke, light, and noise. |
Use hazards and environment carefully. A troop or swarm already changes space, so extra terrain pressure should create choices rather than simply trapping players in damage.
Monster Core Layer
Read group enemies like any Monster Core creature: traits, level, defenses, movement, attacks, reactions, and special abilities. Then ask what the group wants. A disciplined garrison, a terrified militia, an undead troop, a mercenary company, and a cult war band should not behave the same way.
Use creatures by level, encounter use, and creature traits to keep the math and the fiction clear.
Encounter-Building Notes
GM Core encounter budgets still apply. A troop is an encounter creature, not permission to ignore the math, and Battlecry skirmishes start from ordinary encounter building before troop support and objectives get added. Most troop-heavy fights work better when the important enemies sit within a reasonable level band of the party and the fight contains more than one tactical problem.
| Monster family | Troop or garrison use |
|---|---|
| Humanoids | Military units, guards, militia, scouts, raiders, and faction soldiers |
| Undead | Morale-resistant lines, corpse mobs, necromantic war pressure, and horror battlefields |
| Beasts and animals | War beasts, mounts, scouts, supply-line threats, and terrain pressure |
| Constructs | Siege guardians, wall defenders, battlefield engines, and fort security |
| Fiends | Contract armies, terror troops, corrupt commanders, and cruel objective pressure |
| Dragons and giants | Battlefield centerpiece monsters that troops react around, not just enemies with more HP |
Player Counterplay
| Character tool | What it does |
|---|---|
| Area spells | Hit enough bodies to reach a segment, or the whole troop if the effect is wide enough |
| Splash damage | Lets Alchemists and bomb users contribute real answers instead of single-target chip damage |
| Chokepoints | Fighters, Champions, Barbarians, and shield users can make the map smaller for the group |
| Mobility | Monks, Swashbucklers, Rogues, and speed-focused characters escape bad spaces and play objectives |
| Forced movement and terrain | Shove, Trip, Reposition, doors, ledges, bridges, water, pits, and elevation break formation |
| Intimidation and Diplomacy | Morale, surrender, orders, and faction stakes give social characters something real to do |
| Stealth and Deception | Garrisons have watch rotations, alarms, uniforms, signals, and assumptions to exploit |
| Shields and protection | Champions, Guardians, and shield users make rescue scenes playable |
| Recall Knowledge | Identifies whether the problem is swarm, troop, mindless mass, trained unit, or something stranger |
If every character's best turn is still "Strike the troop," the encounter is underusing the concept. If the party has no area damage, splash, mobility, or terrain tools at all, use group threats cautiously. The point is to reward different tools, not to prove that single-target characters chose wrong.
Class And Build Hooks
| Character type | What they get to do |
|---|---|
| Alchemist | Splash damage, consumables, bombs, antidotes, antiplagues, smoke, and problem-specific preparation. |
| Wizard | Area control, battlefield shaping, damage type selection, and preparation payoff. |
| Druid | Area effects, terrain, primal problem solving, and nature-facing swarm stories. |
| Fighter | Chokepoint control, reactive pressure, reach, shields, and protecting weaker allies. |
| Champion | Damage prevention, ally protection, rescue posture, and morale-centered scenes. |
| Guardian | Holding a line, absorbing the troop's attention, and keeping rescue targets alive. |
| Monk | Mobility, escape routes, action efficiency, and reaching objectives through crowded fields. |
| Commander | Battlefield leadership, tactics that treat a troop as a squadmate, and war-scene identity. |
GM Core Battle Procedure
| Step | Why it helps |
|---|---|
| Set an objective | Hold the gate, cross the bridge, save prisoners, burn the nest, protect the ritual, or retreat |
| Use encounter budget | A troop is still an encounter creature, not permission to ignore math |
| Draw lanes | Troops and swarms need space, chokepoints, exits, and places to make formation matter |
| Track morale | A troop might break, reform, retreat, or surrender; a swarm might scatter or pursue instinctively |
| Show aftermath | Casualties, infestation, broken shields, and abandoned gear make group enemies feel real |
Monster Core gives the baseline swarm language. Monster Core 2 expands the number of group-threat tools. GM Core tells you how to turn those tools into a playable encounter instead of a token pile.
GM Tuning
Tune the scene before you touch the math. A troop behind a wall, on a bridge, or guarding a ritual becomes much harder without changing a single number.
| Lever | Harder | Easier |
|---|---|---|
| Starting space | Group begins in formation or already surrounding an objective | Group begins visible and far enough away to plan around |
| Terrain | Narrow lanes, walls, murder holes, difficult ground, smoke, darkness, and elevation favor the group | Multiple routes, cover, ladders, gates, and safe regroup points |
| Objective | Party must rescue, hold, disable, carry, cross, or protect something under pressure | Party only needs to escape, scatter, delay, or defeat a visible leader |
| Information | Players learn the group type only after first contact | Scouts, rumors, banners, drills, and map clues reveal the formation early |
| Support | Commander, caster, hazard, siege gear, or elite creature exploits the group's pressure | Group threat appears alone with one clear job |
| Morale | Troop holds under fear, discipline, or magical command, reforms, or rotates lines | Leader loss, banner loss, casualties, or public embarrassment can rout it |
| Reinforcement clock | More defenders arrive while alarms continue | Players can cut the alarm, block doors, or misdirect reserves |
If you do adjust levels, use elite and weak adjustments lightly, and respect the fact that group-threat mechanics can shift more than expected.
GM Mistakes
Do not hide the objective. Do not run every soldier separately. Do not rout a troop if the players cannot see why it is breaking. Do not forget area effects, splash damage, fear, difficult terrain, and morale, because those are the exact rules that make group enemies feel different from a large monster.
Do not make a garrison omniscient. Defended locations have watch rotations, blind spots, bored guards, panicked recruits, corrupt officers, supply needs, and communication failures. Let smart play find those cracks.
Do not forget aftermath. A routed troop, a captured fort, a broken siege line, or a spared militia should change reputation, local politics, future travel, and who trusts the party.
Core Book Connections
Player Core defines the tools that answer group enemies: area spells, splash damage, movement, forced movement, conditions, and Athletics or Acrobatics escape lines. Player Core 2 adds Alchemist value through splash and consumables, Champion value through protecting allies, and Monk or Swashbuckler value through mobility. The relevant combat chapters are three-action economy, flanking and positioning, and conditions in combat.
Monster Core and Monster Core 2 keep the creature side grounded: traits, level, defenses, movement, senses, and group-threat assumptions. GM Core keeps the encounter honest with budgets, DCs, hazards, subsystems, treasure, and consequences. Battlecry adds the war layer through skirmish encounters, rout checks, and support for war-facing characters like the Commander and Guardian.
You do not need a full war story to use any of this. A town watch, cult mob, skeletal formation, trained guard unit, rat swarm, insect nest, or panic crowd all create group pressure at ordinary adventure scale.
Best Links
Start from the PF2e guide hub, then use Monster Core 2, Monster Core guides, Battlecry, encounter use, creatures by level, creature traits, encounter building, adjusting encounters, GM subsystems, hazards, environment, skirmish warfare, war campaigns, conditions in combat, equipment, consumables, and battle magic.
Hot Take
Troops and swarms are at their worst when they are just big HP bars. They are at their best when the party changes formation, changes targets, or changes the plan, and a garrison earns its place only when the building fights back as hard as the guards do.
