Mobs & AI

The Mobs editor lets you create enemies and creatures. Each mob has combat stats, AI behavior, abilities, loot, and a visual appearance.

Creating a Mob

AI Behaviors

How Mob AI Works

Each mob follows a state machine:

• Idle — standing at spawn, looking for targets within its aggro range
• Patrol — walking a predefined route
• Chase — running toward a detected player
• Combat — using abilities via its weighted ability rotation (see below)
• Return — walking back to spawn if it gets too far away (leash range)

• Aggro range — how far the mob can spot players (default 5 tiles)
• Leash range — max distance from spawn before it resets and walks back (default 15 tiles)

Perception & Stealth

When the stealth / encounterAI features are on, mobs use real perception instead of a flat radius. Each mob's perception profile has a sight radius, a sight cone (degrees), a hearing radius, and light sensitivity — so a stealthed player can slip past a mob's back or stay out of its cone and lamplight. This feeds the area-of-interest and aggro checks server-side.

Weighted Ability Rotation

Rather than a fixed rotation, each mob ability carries a weight plus conditions — min/max range, the mob's own HP %, the target's HP %, and a minimum number of targets caught in an AoE. The AI picks among eligible abilities by weight, so casters kite, healers top up allies, and bombers wait for clustered targets.

Element & Status Traits

Mobs can be tuned defensively and offensively:

• Element — an elementId plus element rates (resist/weakness multipliers) that plug into the element effectiveness matrix.
• Status rates & immunities — per-status susceptibility multipliers and hard immunities (e.g. a slime that can't be poisoned).

Encounter Scripts (Bosses & Packs)

For bosses and coordinated groups, the Encounters editor defines data-driven encounter scripts:

• Phases triggered by HP thresholds or elapsed time
• Actions per phase — cast an ability, spawn adds, play a telegraph, or enrage
• Pack behavior — shared aggro on pull, a leader role, and formation, so a whole camp reacts together

Death VFX

Each mob can select a per-mob Death VFX from the VFX editor. Leave it unset and the mob uses the engine default (default.death_burst), which is itself an editable VFX definition.

Monster Parties

Group up to 5 mobs into a Monster Party with assigned roles:

• Tank — high HP, draws attention
• Damage — high attack, less durable
• Support — heals or buffs other mobs

Spawn Rules

A spawn rule populates one zone with one monster party. Author them in Mobs → Spawn Rules.

How the conditions behave

A rule with a time or weather condition is checked continuously, not just at world start:

• When the condition starts matching, the pack spawns (up to max count) within about ten seconds.
• When it stops matching, the pack is removed — except any mob currently fighting a player. Those finish their fight and simply don't come back.
• A pack that died during its window waits for the window to return instead of respawning outside it. A night-only pack killed at 3am comes back the next night, not at noon.

How the biome filter behaves

The biome is a real constraint: the spawner sweeps the zone for tiles painted with that biome and places the party there, even when the region is a small painted patch on a big map.

The one exception is a zone where the biome isn't painted anywhere — typically an imported map whose tiles carry no biome tags. Rather than leaving the map empty, the pack spawns on any walkable tile and the server log says so:

[MobAI] Spawned 24 mobs in 6 party groups (24 from DB rules, 3 placed outside
their rule biome — the zone has no tiles tagged with that biome (paint biome
regions to constrain them))

If you see that line, paint the biome region you meant and re-publish.

Gotchas

• Mobs never spawn on top of you — a candidate tile within 5 tiles of a player, inside a no-spawn land claim, or on unwalkable terrain is skipped.
• Editing rules re-seeds the zone. Publishing spawn-rule changes removes the mobs those rules created and spawns fresh ones; hand-placed and event mobs are untouched.
• World events can scale respawns. A "spawn rate" world event multiplies every rule's interval while it runs.

Equipment

Mobs can equip up to 4 gear pieces, which affect their appearance and stats. Equipped items can also appear in the mob's loot table.