Step-by-Step Enemy Creation

Documentation Unreal Engine AI Tutorial

Build one enemy end to end: pawn, controller, a moveset with a combo, a weapon that lands its hits, and something to fight.

One enemy, from an empty project to a real fight: it holds its range, circles, opens with a light attack, chains into a heavy, and gives ground when you crowd it.

Set it up

5 minutes
  1. 1

    Make the pawn and the controller

    Right-click in the Content Browser, Blueprint Class, All Classes, and pick Enemy Character Base. Name it BP_Grunt, assign your skeletal mesh, and size the capsule.
    Do it again from Enemy Controller Base and name that one BP_GruntController.
    Both arrive carrying every component the AI needs.
  2. 2

    Create the moveset

    Right-click in the Content Browser, SEC, Action Set, and name it DA_ActionSet_Grunt. It opens on its own card canvas.
    Content Browser
    ▸ Content
    Right-click in the Content Browser, SEC, Action Set.
    Right-click the canvas, choose Add Action, and name the Action ID LightAttack. Set Ability Class to GA_SEC_MontageAbility, which ships with the plugin, and point the Montage underneath it at your attack animation. Add a Distance Scorer to the card's Scoring > Scorers list.
  3. 3

    Create the AI Config

    Right-click in the Content Browser, SEC, Enemy AI Config, and name it EnemyConfig_Grunt.
    Content Browser
    ▸ Content
    Right-click in the Content Browser, SEC, Enemy AI Config.
    Set Default Action Set to the moveset and Target Selector to Closest Target Selector.
    The enemy also needs senses. Create an Awareness Config from the same SEC menu, name it DA_Awareness_Grunt, leave its defaults alone, and point the AI Config's Awareness Config field at it. Those defaults are a working guard: 1500 cm of sight across a 180 degree cone, 1200 cm of hearing, and a damage sense that reveals whoever hits it from behind.
    EnemyConfig_Grunt
    ▾Details
    Target SelectorNone
    Awareness Config
    None▾
    Manage Action Sets Automatically
    Default Action Set
    None▾
    Target Selector and Awareness Config both ship empty, and an enemy missing either one stands still with nothing in the log. The rest of the config has working defaults.
  4. 4

    Wire the pawn to both

    Open BP_Grunt, go to Class Defaults, and set AI Controller Class to BP_GruntController and AI Config to EnemyConfig_Grunt.
    BP_Grunt
    ▾Class Defaults
    AI Controller ClassNone
    AI Config
    None▾
    The controller reads the pawn's config on possession, so one controller class serves many enemy types.
  5. 5

    Register the player, and play

    On the player pawn's Event BeginPlay, add the AICombat Role Subsystem node and call Register Combat Target with Target Actor set to Self and Auto Assign Unassigned ticked.
    Player pawn · Event BeginPlay
    AICombatRoleSubsystem
    Register Combat Target
    Target is AICombat Role Subsystem
    Target
    Target ActorSelf
    Auto Assign Unassigned
    Reevaluate Existing
    Drop BP_Grunt into a level with a built NavMesh and press Play. Walk into its sight cone: it closes to about 400 cm, circles you, and swings when you come into range.
An enemy with no registered combat target does nothing at all: no movement, no attacks, no reactions. Fill in every field above and the enemy still stands there, and that last step is what is missing. See Targeting.
The rest of this page turns that one attack into a fight.

Build the pawn and the controller

BP_Grunt arrives with an ability system, melee traces, vitals, defenses, equipment, and the action, reaction and role components. BP_GruntController arrives with the parts that decide: movement, action scoring, reactions, awareness, threat, and the brain that ticks them.
Set the pawn up like any character. Assign the skeletal mesh, size the capsule to it, and set Max Walk Speed on its Character Movement component to around 400.
Nothing else on either Blueprint needs touching to get a fight running.
AlternativeUse a character you already have
Reparent it instead of rebuilding it.
  1. Open your character Blueprint.
  2. File > Reparent Blueprint, and pick Enemy Character Base.
  3. Your existing components, variables and graphs stay, and you inherit the ability system, the combat components and the combat interfaces.
  4. Delete any duplicate the Blueprint already added itself, so only the inherited copies remain.
  5. Set AI Config on Class Defaults, then assign the mesh and the controller as usual.
Reparenting also starts the ability system up, which a Blueprint cannot do on its own. An ability whose ability system never got that call refuses to activate and says nothing about why.
A character that has to inherit from some other C++ class cannot reparent. API Reference covers rebuilding the pawn from a different base.
AlternativeUse an AI controller you already have
Reparent it to Enemy Controller Base the same way, and you inherit the evaluators, the behavior-tree helper, the committed-attack rotation lock, smooth focus, and awareness-based facing.
Adding the components to a bare AI Controller is not the same thing. The base holds the pawn's facing during an attack and turns it toward a target's last-known location, and attack abilities read the controller for that lock. A plain controller keeps tracking the player mid-swing and carries none of that facing work.
The base puts that on Blueprint nodes: Lock Rotation By and Unlock Rotation By freeze and release facing around a committed attack, and Is Rotation Locked reads the current state. Override Get Desired Facing Location to redirect where the pawn looks each frame.

Build the moveset

One action is enough to see an enemy attack. A fight needs several that win at different ranges and moments. Open DA_ActionSet_Grunt and add the three below.
A new card ships with an empty Scorers list, so it scores the same at every distance and angle until you add one.
Details
Scoring
Selection Weight
1.0
Scorers
0 Array elements
Gates
0 Array elements
Both lists empty, so the action scores on weight alone.
score = Weight × Distance · (Stamina pass) × Yours
Scorers, class picker
Angle Scorer
Attribute Scorer
Distance Scorer
Health Scorer
Speed Scorer
Vital Scorer
Each scorer multiplies in; each gate can veto. Mix built-ins with Blueprint subclasses of your own.

The light attack

Identity
Action ID
LightAttack
Enabled
Execution
Execution Method
Gameplay Ability
Ability Class
GA_SEC_MontageAbility
Montage
AM_Attack_Light
Scoring
Selection Weight
1
Scorers
2 Array elements
Gates
0 Array elements
Index [ 0 ] Distance Scorer
Min Value
0
Optimal Min
100
Optimal Max
250
Max Value
500
Index [ 1 ] Angle Scorer
Min Value
0
Optimal Min
0
Optimal Max
30
Max Value
90
Chaining
Chain Links
1 Array element
Target Action ID
HeavyAttack
Bonus Multiplier
1.5
Cooldown
Cooldown Duration
2
Initial Cooldown
1
Distance ranges are in centimetres and angle ranges in degrees. Each one scores 1 between Optimal Min and Optimal Max and falls to 0 at Min Value and Max Value, so this attack peaks between 100 and 250 cm, fades out by 500, and wants the enemy facing you. Initial Cooldown keeps it from being the opening move. The Chain Links row is what feeds the heavy attack below.

The heavy attack, as the combo finisher

Identity
Action ID
HeavyAttack
Enabled
Execution
Execution Method
Gameplay Ability
Ability Class
GA_SEC_MontageAbility
Montage
AM_Attack_Heavy
Scoring
Selection Weight
0.8
Risk Penalty
1.5
Scorers
1 Array element
Index [ 0 ] Distance Scorer
Min Value
0
Optimal Min
150
Optimal Max
300
Max Value
450
Cooldown
Cooldown Duration
4
A Selection Weight under 1 and a Risk Penalty over 1 both bias against this coming up on its own, which is what leaves room for the combo. The light attack's chain link names HeavyAttack with a Bonus Multiplier of 1.5, so the heavy scores 50% higher for a short window once the light completes.
An interrupt or a cancel clears that window, so a parried enemy cannot combo out of the hit it took.

The retreat, for when you crowd it

Identity
Action ID
QuickRetreat
Enabled
Execution
Execution Method
Behavior Tree Sequence
Behavior Tree Sequence
1 Array element
[0]
BT_QuickBackstep
Scoring
Selection Weight
1.5
Scorers
1 Array element
Tag Score Multipliers
YourGame.State.PlayerAttacking = 2.0
Index [ 0 ] Distance Scorer
Min Value
0
Optimal Min
0
Optimal Max
100
Max Value
200
Cooldown
Cooldown Duration
3
This one runs a behavior tree rather than an ability. Build BT_QuickBackstep as a one-node tree around the Make Distance task, which backs the pawn away from its target until it reaches a distance you set.
Its Distance Scorer peaks close in, from 0 to 100 cm, so it wins exactly when you have crowded the enemy. The Tag Score Multipliers row is optional, and the tag in it comes from your project rather than the plugin. YourGame.State.PlayerAttacking stands in for a tag you define yourself and apply for the length of a player swing, which doubles the retreat score while the player is committed to an attack. Leave the row empty and the retreat still picks itself on distance alone.
Tag Score Multipliers takes any gameplay tag and scales the score while the AI, the target or the world holds it. The plugin declares SEC.State.Staggered for a reaction montage to hold, so 2.0 on that tag makes a punish. A tag of your own works the same way: YourGame.Phase.BossPhase2 at 1.3 makes an enemy meaner late in a fight. The Action System covers scoring in full.

Make the swings land

The montages play, but nothing takes damage until a swept trace runs over the strike frames.
  1. Build the weapon on SEC Weapon Base, and place sockets at the hilt and the tip of its mesh.
  2. Add one Trace Sockets entry and set its Shape to Capsule Two Point, which reveals End Socket Or Bone Name. Name the hilt socket in Socket Or Bone Name and the tip in End Socket Or Bone Name, so the capsule spans the blade. The default Sphere sweeps a single point.
  3. Select the pawn's SEC Equipment Component and add the weapon class to Starting Loadout, with Use As Weapon ticked.
  4. Open each attack montage, add a SEC Melee Trace Window notify state, and drag it across the frames that connect.
  5. Set the window's Damage Config. Six ship under Core/Damage, one per damage type.
Weapons covers the weapon Blueprint, and Melee Trace covers the sweep shapes, damage and impact effects.
A weapon can also carry its own moveset in Weapon Action Set, which wins over the AI Config while the enemy holds it. Hand the same skeleton a bow and it fights like an archer.
A trace window sweeps sockets that were registered before it opened, and a weapon registers its own the moment the enemy equips it. An enemy that spawns unarmed swings through everything. The Output Log names any socket ID a window asked for that nothing registered.

Give it ground to hold

The Movement Evaluator on the controller ships with a working default, so the enemy already closes to 400 cm and circles. Author a Movement Behavior Profile when you want that range to be part of the enemy's design: 250 cm for a brawler, 600 for something that hangs back.
Create one under SEC, Movement Behavior Profile, set Desired Distance, then set Default Movement Profile on the AI Config. See Movement System.

Let it answer a hit

An enemy that only attacks reads as a punching bag. Author a Reaction Set with a flinch, a parry or a dodge, wire a trigger to each on its canvas, and set Default Reaction Set on the AI Config. See Reaction System.

Debug it

Press Play and turn the overlays on:
SEC.Debug.Scoring 1              // Score list above each enemy, highest first
SEC.Debug.Actions 1              // Cooldown list above each enemy
SEC.Debug.Movement 1             // Movement layer, strafe side and heading
SEC.Debug.Role 1                 // Name and combat role, coloured by role
SEC.Debug.Melee.DrawTracing 1    // The swept shape, every frame a window is open
SEC.Debug.All 1 turns every overlay on at once, and SEC.Debug.WatchPawn <name> narrows them to one enemy.
For a record you can scroll back through, SEC.Debug.LogActionDecisions 1 prints why each action scored what it did:
LogEvaluation: [EvalComp] LightAttack: Ctx=0.95 Nov=1.00 Chain=1.00 Risk=1.00 Runtime=1.00 Custom=0.95 -> 0.90
LogEvaluation: [EvalComp] HeavyAttack: Ctx=0.40 Nov=1.00 Chain=1.00 Risk=0.67 Runtime=1.00 Custom=0.40 -> 0.11
LogEvaluation: [EvalComp] Committed to: LightAttack (score 0.90)
Every scorer on a card folds into the single Custom figure rather than getting a column of its own. To read one scorer at a time, open the Action Set while the game runs: the Action Set Editor lights each card up with its live score, its cooldown, and the gate that refused it.
Expect the enemy to close to its range, circle, open with a light attack, sometimes chain into the heavy, and back off when you crowd it.
AdvancedIt stands there and does nothing
In the order worth checking:
  • No registered combat target. Nothing selects a target on its own, and this failure is silent. It is the common one.
  • Awareness Config is empty on the AI Config. The controller carries an awareness component whatever you set there, so an enemy with that field empty senses nothing, holds each target at Unknown, and never reaches its combat phase. Run SEC.Debug.Awareness 1 to read the state above its head.
  • No NavMesh. Add a NavMeshBoundsVolume and build navigation.
  • Target Selector is empty on the AI Config and in project settings. An enemy possessed before the player registers never picks a target up.
  • AI Controller Class on the pawn still points at the engine default rather than BP_GruntController.
  • AI Config is empty on both the pawn and the controller, so no set resolves.
AdvancedIt picks a move, and nothing happens
  • The ability has no activation graph. An ability implementing neither Activate Ability nor Activate Ability From Event starts and never ends, and the enemy locks up behind it. Ability Timeout on the execution method cuts a hung ability off and names it in the log.
  • The Montage Payload has no montage. Saving the Action Set reports this into the Asset Check message log.
  • The Action ID is empty. An action with no ID cannot be found again, so the execution that follows the poll drops it. Nothing prints unless SEC.Debug.LogActionExecution 1 is on. Name it on the canvas.
  • Enabled is unticked, which also stops the ability being granted.
  • Manage Action Sets Automatically is unticked on the AI Config, which applies no set at all.
AdvancedIt repeats one move, or swings from across the room
Both come from missing scorers. A card with an empty Scorers list scores the same everywhere, so it wins at every range and the others never get a look in.
Give each action its own Distance Scorer with a different band, and an Angle Scorer where facing matters. Then set Cooldown Duration, which defaults to 0, and Max Consecutive Uses to force a switch after a set number of repeats.
Recovery on the AI Config puts a gap between any two attacks rather than between two uses of one attack. It defaults to 0, so it stays off until you set Action Recovery Time.
AdvancedThe weapon swings through the player
  • The Socket IDs on the montage notify do not match the weapon's Trace Sockets ID. They are matched by name.
  • Use As Weapon is unticked on the loadout entry, so the weapon spawns and attaches while none of it reaches the enemy.
  • The window sits on the wrong frames. SEC.Debug.Melee.DrawTracing 1 draws the swept shape so you can see where it opened.
  • The target refuses the hit. A pawn answering as SEC Damageable can block, parry or shrug a hit off. See Defense System.
AlternativeStructure the fight with a StateTree
Leave Default State Tree empty on the AI Config and a native loop runs the combat you built: gather context, move, then score and run the best action.
Set it to StateTree_SEC_Core, which ships in the showcase content, or author your own, when the enemy needs structure the loop has no opinion about: patrol, investigate, return home, boss phases. The graph nodes are on StateTree Tasks.
Both routes use the same Action Sets, Reaction Sets and movement profiles, so swapping between them changes no data.
AlternativeGive each combat role its own moveset
Role Action Sets on the AI Config hands each combat role a different set, so a Flanker opens differently from an Attacker, and the swap happens on its own when the role changes. Role Reaction Sets and Role Movement Profiles do the same for reactions and positioning.
Fill in Default Action Set alongside them. A role you did not list falls back to it, and an enemy that has not been assigned a role gets nothing without it.
AdvancedEditing while the game runs
Tuning values on an existing action during Play In Editor is safe, and the running enemy picks the change up on its next decision. Adding, deleting or renaming an action goes through, but a running enemy holds positions in the list and the entries move underneath it. The editor warns you once per session in the message log when you do it. Restart Play In Editor after those.