API Overview

The RPGMobs API allows other Hytale mods to react to RPG mob events, inspect mob state, and modify behavior at runtime. It ships as a separate RPGMobs-api artifact so your mod only depends on the lightweight API interfaces, not the full plugin.

Setup

Dependency

Add the API JAR as a compile-only dependency in your build.gradle:

dependencies {
    compileOnly files('libs/RPGMobs-API-1.3.0.jar')
}

Or if published to a Maven repository:

dependencies {
    compileOnly 'Frotty27:RPGMobs-api:1.3.0'
}

The -javadoc.jar and -sources.jar are available as additional downloads. Place all three in your libs/ folder for full IDE support (autocomplete, inline docs, click-to-source).

Mod Manifest

Declare RPGMobs as a dependency in your mod’s manifest.json so Hytale loads it before your mod:

{
  "Dependencies": {
    "Frotty27:RPGMobs": "*"
  }
}

Entry Point

All API access goes through the static RPGMobsAPI class:

import com.frotty27.rpgmobs.api.RPGMobsAPI;

// Register a listener
RPGMobsAPI.registerListener(myListener);

// Query mob state
RPGMobsAPI.query().getTier(entityRef);

// Unregister when your mod shuts down
RPGMobsAPI.unregisterListener(myListener);

If RPGMobs has not initialized yet, calling these methods throws RPGMobsNotInitializedException.

Event System

Implement IRPGMobsEventListener and override the events you care about. All handler methods have default no-op implementations, so you only need to override what you use.

import com.frotty27.rpgmobs.api.IRPGMobsEventListener;
import com.frotty27.rpgmobs.api.events.*;

public class MyEliteListener implements IRPGMobsEventListener {

    @Override
    public void onRPGMobSpawned(RPGMobsSpawnedEvent event) {
        int tier = event.getTier();
        // Cancel the spawn if needed
        // event.setCancelled(true);
    }

    @Override
    public void onRPGMobDrops(RPGMobsDropsEvent event) {
        // Add custom items to the drop list
        event.getDrops().add(myCustomItem);
    }

    @Override
    public void onRPGMobDamageDealt(RPGMobsDamageDealtEvent event) {
        // Reduce elite damage by 20%
        event.setMultiplier(event.getMultiplier() * 0.8f);
    }
}

RPGMobsAPI.registerListener(new MyEliteListener());

Available Events

Event	Fired when	Cancellable	Mutable fields
`RPGMobsSpawnedEvent`	Elite enters the world	Yes	-
`RPGMobsDeathEvent`	Elite or minion dies	No	`isMinion()`
`RPGMobsDropsEvent`	Loot is about to spawn	Yes	`getDrops()` (live list)
`RPGMobsDamageDealtEvent`	Elite deals outgoing damage	Yes	`setMultiplier(float)`
`RPGMobsDamageReceivedEvent`	Elite takes incoming damage	No	-
`RPGMobsAbilityStartedEvent`	Ability execution begins	Yes	-
`RPGMobsAbilityCompletedEvent`	Ability finishes normally	No	-
`RPGMobsAbilityInterruptedEvent`	Ability was interrupted	No	`getReason()`
`RPGMobsAggroEvent`	Elite targets an entity	No	`getTargetRef()`
`RPGMobsDeaggroEvent`	Elite loses its target	No	-
`RPGMobsScalingAppliedEvent`	Scaling parameters computed	No	`getHealthMultiplier()`, `getDamageMultiplier()`, `getModelScale()`
`RPGMobsReconcileEvent`	Config reconciliation pass	No	`getWorldName()`, `getEntityCount()`

Base Event Fields

Every event extends RPGMobsEvent which provides:

getWorld() - the World in which the event occurred (since 1.1.0)
getEntityRef() - the RPG mob’s Ref<EntityStore>
getEntityUuid() - the entity’s UUID, or null if unavailable (since 1.1.0)
getTier() - zero-based tier index (0 = Tier 1, 4 = Tier 5)
getRoleName() - the NPC role identifier (e.g. "Skeleton_Frost_Knight")

Cancelling Events

Events that implement ICancellable can be cancelled to prevent the action:

@Override
public void onRPGMobSpawned(RPGMobsSpawnedEvent event) {
    if (event.getTier() >= 4) {
        event.setCancelled(true); // Block Tier 5 spawns
    }
}

Cancellable events: RPGMobsSpawnedEvent, RPGMobsDropsEvent, RPGMobsDamageDealtEvent, RPGMobsAbilityStartedEvent.

Query API

The Query API provides read-only access to any RPG mob’s current state. Access it via RPGMobsAPI.query().

import com.frotty27.rpgmobs.api.query.IRPGMobsQueryAPI;

IRPGMobsQueryAPI query = RPGMobsAPI.query();

Identity

Method	Returns	Description
`isRPGMob(ref)`	`boolean`	Whether the entity is an RPGMobs elite
`isMinion(ref)`	`boolean`	Whether the entity is a summoned minion
`getTier(ref)`	`Optional<Integer>`	Zero-based tier index

Scaling

Method	Returns	Description
`getHealthMultiplier(ref)`	`Optional<Float>`	Applied health multiplier
`getDamageMultiplier(ref)`	`Optional<Float>`	Applied damage multiplier
`getModelScale(ref)`	`Optional<Float>`	Visual size scale
`isHealthFinalized(ref)`	`boolean`	Whether health scaling has been verified

Progression

Method	Returns	Description
`getSpawnDistance(ref)`	`Optional<Float>`	Distance from world origin at spawn
`getDistanceHealthBonus(ref)`	`Optional<Float>`	Bonus health from distance
`getDistanceDamageBonus(ref)`	`Optional<Float>`	Bonus damage from distance

Combat

Method	Returns	Description
`isInCombat(ref)`	`boolean`	Whether the mob has an active target
`getLastAggroTarget(ref)`	`Optional<Ref<EntityStore>>`	Current or last aggro target
`getLastAggroTick(ref)`	`Optional<Long>`	Server tick of last aggro event

Summons

Method	Returns	Description
`getSummonedMinionCount(ref)`	`Optional<Integer>`	Number of active summoned minions

Query Examples

Check if an entity is an elite and read its tier

IRPGMobsQueryAPI query = RPGMobsAPI.query();

if (query.isRPGMob(entityRef)) {
    int tier = query.getTier(entityRef).orElse(0);
    System.out.println("RPG mob detected  -  Tier " + (tier + 1));
}

IRPGMobsQueryAPI query = RPGMobsAPI.query();

Optional<Float> health = query.getHealthMultiplier(entityRef);
Optional<Float> damage = query.getDamageMultiplier(entityRef);
Optional<Float> scale  = query.getModelScale(entityRef);

health.ifPresent(h -> System.out.println("Health multiplier: " + h + "x"));
damage.ifPresent(d -> System.out.println("Damage multiplier: " + d + "x"));
scale.ifPresent(s ->  System.out.println("Model scale: " + s + "x"));

Check combat state and current target

IRPGMobsQueryAPI query = RPGMobsAPI.query();

if (query.isInCombat(entityRef)) {
    query.getLastAggroTarget(entityRef).ifPresent(targetRef -> {
        System.out.println("Currently fighting a target");
    });
    query.getLastAggroTick(entityRef).ifPresent(tick -> {
        System.out.println("Aggro started at server tick " + tick);
    });
}

Read distance-based progression bonuses

IRPGMobsQueryAPI query = RPGMobsAPI.query();

query.getSpawnDistance(entityRef).ifPresent(distance -> {
    System.out.println("Spawned " + distance + "m from world origin");
});

Optional<Float> healthBonus = query.getDistanceHealthBonus(entityRef);
Optional<Float> damageBonus = query.getDistanceDamageBonus(entityRef);

if (healthBonus.isPresent() && damageBonus.isPresent()) {
    System.out.println("Distance bonuses  -  health: +" + healthBonus.get()
        + "x, damage: +" + damageBonus.get() + "x");
}

Monitor summoned minions

IRPGMobsQueryAPI query = RPGMobsAPI.query();

if (query.isMinion(entityRef)) {
    System.out.println("This entity is a summoned minion");
}

query.getSummonedMinionCount(entityRef).ifPresent(count -> {
    System.out.println("Active minions: " + count);
});

Inspect combat state (since 1.2.0)

IRPGMobsQueryAPI query = RPGMobsAPI.query();

// Which mob rule matched this elite
String ruleKey = query.getMatchedMobRuleKey(entityRef, store);
// e.g. "Skeleton_Fighter", "Trork_Warrior"

// Currently executing ability (null if idle)
String abilityId = query.getActiveAbilityId(entityRef, store);
// e.g. "multi_slash_medium", "charge_leap", null

// Combat style driving the CAE behavior
String style = query.getCombatStyle(entityRef, store);
// e.g. "Disciplined", "Berserker", "Tactical", "Chaotic"

Filter minion deaths

@Override
public void onRPGMobDeath(RPGMobsDeathEvent event) {
    if (event.isMinion()) {
        // Skip minion deaths  -  only reward XP for real elites
        return;
    }
    int tier = event.getTier();
    UUID uuid = event.getEntityUuid();
    World world = event.getWorld();
    System.out.println("Elite killed in " + world + "  -  tier " + (tier + 1));
}

Ability IDs

Abilities are identified by string IDs passed in ability events (RPGMobsAbilityStartedEvent, RPGMobsAbilityCompletedEvent, RPGMobsAbilityInterruptedEvent). The built-in ability IDs are:

ID	Description
`"charge_leap"`	Leap toward target with area slam damage
`"heal_leap"`	Jump to safety and drink a healing potion
`"undead_summon"`	Spawn role-based reinforcements
`"dodge_roll"`	Reactive/preemptive lateral dodge with invulnerability frames
`"multi_slash_short"`	1-2 hit quick strikes (3 random variations per weapon type)
`"multi_slash_medium"`	2-4 hit combos (2 random variations per weapon type)
`"multi_slash_long"`	4-6 hit full combos (1 variation per weapon type)
`"enrage"`	Berserk fist-fighting mode ending in exhaustion death
`"volley"`	Ranged projectile burst for bow/crossbow/gun wielders

Example: Full Integration

import com.frotty27.rpgmobs.api.RPGMobsAPI;
import com.frotty27.rpgmobs.api.IRPGMobsEventListener;
import com.frotty27.rpgmobs.api.events.*;

public class MyMod implements IRPGMobsEventListener {

    public void onEnable() {
        RPGMobsAPI.registerListener(this);
    }

    public void onDisable() {
        RPGMobsAPI.unregisterListener(this);
    }

    @Override
    public void onRPGMobSpawned(RPGMobsSpawnedEvent event) {
        // Log spawns for analytics
        System.out.println("Elite spawned: tier=" + event.getTier()
            + " role=" + event.getRoleName());
    }

    @Override
    public void onRPGMobDrops(RPGMobsDropsEvent event) {
        // Double drops for Tier 5 elites
        if (event.getTier() == 4) {
            var drops = event.getDrops();
            drops.addAll(new ArrayList<>(drops));
        }
    }

    @Override
    public void onRPGMobDamageDealt(RPGMobsDamageDealtEvent event) {
        // Check if mob is far from spawn using query API
        var distance = RPGMobsAPI.query()
            .getSpawnDistance(event.getEntityRef());

        if (distance.isPresent() && distance.get() > 5000f) {
            // Extra 10% damage for mobs far from spawn
            event.setMultiplier(event.getMultiplier() * 1.1f);
        }
    }
}

Spawn API (since 1.3.0)

The Spawn API lets other mods programmatically create RPGMobs elites. Access it via RPGMobsAPI.spawn().

Quick Reference

import com.frotty27.rpgmobs.api.RPGMobsAPI;
import com.frotty27.rpgmobs.api.spawn.SpawnResult;

Method	Description
`RPGMobsAPI.spawn().spawnElite(world, roleName, tier, position, rotation, weaponCategory)`	Creates an NPC and promotes it to an elite in one call
`RPGMobsAPI.spawn().applyEliteTier(world, npcRef, tier, weaponCategory)`	Promotes an already-spawned NPC to an elite

Parameters:

Parameter	Type	Description
`world`	`World`	The world to spawn in
`roleName`	`String`	NPC role name (e.g. `"Skeleton_Fighter"`, `"Trork_Warrior"`, `"Goblin_Duke"`)
`tier`	`int`	Tier number 1-5 (clamped if out of range). 1 = Common, 5 = Legendary
`position`	`Vector3d`	Spawn position in world coordinates
`rotation`	`@Nullable Vector3f`	Spawn rotation, or `null` for default
`weaponCategory`	`@Nullable String`	Weapon category override (see table below), or `null` to use the mob rule’s default
`npcRef`	`Ref<EntityStore>`	(applyEliteTier only) Reference to an existing NPC entity

Weapon Categories

Pass one of these exact strings as weaponCategory to force the elite to spawn with that weapon type. Pass null to let RPGMobs pick based on the mob rule’s configured categories.

Category	Type	Example weapons
`"Swords"`	Melee	Iron Sword, Steel Sword
`"Longswords"`	Melee	Steel Longsword, Adamantite Longsword
`"Daggers"`	Melee	Iron Daggers, Bone Daggers
`"Axes"`	Melee	Iron Axe, Steel Axe
`"Battleaxes"`	Melee	Iron Battleaxe, Adamantite Battleaxe
`"Maces"`	Melee	Iron Mace, Steel Mace
`"Clubs"`	Melee	Wooden Club, Bone Club
`"ClubsFlail"`	Melee	Flail variants
`"Spears"`	Melee	Iron Spear, Steel Spear
`"Pickaxes"`	Melee	Iron Pickaxe, Steel Pickaxe
`"Shortbows"`	Ranged	Shortbow variants (uses vanilla ranged AI)
`"Crossbows"`	Ranged	Crossbow variants (uses vanilla ranged AI)
`"Guns"`	Ranged	Gun variants (uses vanilla ranged AI)
`"Staves"`	Ranged	Staff variants (uses vanilla ranged AI)
`"Spellbooks"`	Ranged	Spellbook variants (uses vanilla ranged AI)

Ranged weapon categories use vanilla Hytale AI instead of the CAE combat system.

Spawn a New Elite

SpawnResult result = RPGMobsAPI.spawn().spawnElite(
    world,                  // the world to spawn in
    "Skeleton_Fighter",     // NPC role name
    3,                      // tier (1-5)
    position,               // Vector3d spawn position
    null,                   // rotation (null = default)
    null                    // weapon category (null = mob rule default)
);

if (result instanceof SpawnResult.Success s) {
    Ref<EntityStore> eliteRef = s.entityRef();  // the spawned entity
    int tier = s.tier();                        // 0-4 (zero-indexed)
    String role = s.roleName();                 // resolved role name
}

Elite-ify an Existing NPC

If you already spawned an NPC via NPCPlugin and want to promote it:

SpawnResult result = RPGMobsAPI.spawn().applyEliteTier(
    world, existingNpcRef, 5, "Longswords");

Force a Weapon Category

// Spawn a T4 Trork with an axe
RPGMobsAPI.spawn().spawnElite(
    world, "Trork_Warrior", 4, pos, null, "Axes");

// Spawn a T5 Skeleton with a longsword
RPGMobsAPI.spawn().spawnElite(
    world, "Skeleton_Fighter", 5, pos, null, "Longswords");

Handle Failures

SpawnResult is a sealed interface. Check success or match on the failure reason:

SpawnResult result = RPGMobsAPI.spawn().spawnElite(world, "Skeleton_Fighter", 3, pos, null, null);

if (result.isSuccess()) {
    var success = (SpawnResult.Success) result;
    // use success.entityRef()
    return;
}

var failure = (SpawnResult.Failure) result;
switch (failure.reason()) {
    case CONFIG_NOT_LOADED       -> log("RPGMobs config not ready");
    case NPC_SPAWN_FAILED        -> log("Hytale couldn't spawn the NPC");
    case NO_MOB_RULE             -> log("No mob rule matches this role");
    case MOB_RULE_DISABLED       -> log("Mob rule is disabled in this world");
    case RPGMOBS_DISABLED_IN_WORLD -> log("RPGMobs is off in this world");
    case EVENT_CANCELLED         -> log("A listener cancelled the spawn");
    case NOT_INITIALIZED         -> log("RPGMobs hasn't started yet");
    case TIER_APPLY_FAILED       -> log("Internal error: " + failure.message());
}

Threading

All spawn methods must be called on the world’s thread. From other threads, wrap in world.execute():

world.execute(() -> {
    RPGMobsAPI.spawn().spawnElite(world, "Goblin_Duke", 5, pos, null, null);
});

Thread Safety

Event callbacks are dispatched from the server’s main tick thread. Do not perform blocking I/O or long-running computations inside event handlers. If you need async processing, queue work to a separate thread and return immediately. The Query API reads component data from the entity store and should only be called from contexts where the store is accessible (event handlers, tick systems, or world.execute() callbacks).

Getting Started

Admin UI

File Configuration

Developer API

Reference

Setup

Dependency

Mod Manifest

Entry Point

Event System

Available Events

Base Event Fields

Cancelling Events

Query API

Identity

Scaling

Progression

Combat

Summons

Query Examples

Check if an entity is an elite and read its tier

Read scaling values for a HUD or tooltip

Check combat state and current target

Read distance-based progression bonuses

Monitor summoned minions

Inspect combat state (since 1.2.0)

Filter minion deaths

Ability IDs

Example: Full Integration

Spawn API (since 1.3.0)

Quick Reference

Weapon Categories

Spawn a New Elite

Elite-ify an Existing NPC

Force a Weapon Category

Handle Failures

Threading

Thread Safety

Getting Started

Admin UI

File Configuration

Developer API

Reference

​Setup

​Dependency

​Mod Manifest

​Entry Point

​Event System

​Available Events

​Base Event Fields

​Cancelling Events

​Query API

​Identity

​Scaling

​Progression

​Combat

​Summons

​Query Examples

​Check if an entity is an elite and read its tier

​Read scaling values for a HUD or tooltip

​Check combat state and current target

​Read distance-based progression bonuses

​Monitor summoned minions

​Inspect combat state (since 1.2.0)

​Filter minion deaths

​Ability IDs

​Example: Full Integration

​Spawn API (since 1.3.0)

​Quick Reference

​Weapon Categories

​Spawn a New Elite

​Elite-ify an Existing NPC

​Force a Weapon Category

​Handle Failures

​Threading

​Thread Safety

Setup

Dependency

Mod Manifest

Entry Point

Event System

Available Events

Base Event Fields

Cancelling Events

Query API

Identity

Scaling

Progression

Combat

Summons

Query Examples

Check if an entity is an elite and read its tier

Read scaling values for a HUD or tooltip

Check combat state and current target

Read distance-based progression bonuses

Monitor summoned minions

Inspect combat state (since 1.2.0)

Filter minion deaths

Ability IDs

Example: Full Integration

Spawn API (since 1.3.0)

Quick Reference

Weapon Categories

Spawn a New Elite

Elite-ify an Existing NPC

Force a Weapon Category

Handle Failures

Threading

Thread Safety