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Merm

Based on game build 714014 | Last updated: 2026-03-05

Overview​

The merm prefabs implement the core behavior and lifecycle for Merm NPCs in DST, including regular Merms, Merm Guards, Shadow Merms, and Lunar Merms. It handles combat targeting, loyalty systems (via the follower component), royal status effects (via mermkingmanager), special alignment-based mutations (lunar/shadow), and home-finding mechanics. Key interactions include trading (via trader), inventory management (via inventory), and dynamic state transitions when leaders change or conditions like health threshold are met.

Usage example​

-- Example: Hire a Merm and add loyalty time
local merm = SpawnPrefab("merm")
merm.Transform:SetPosition(inst.Transform:GetWorldPosition())
merm:AddTag("playermerm") -- Allow interaction by the current player

-- Feed the merm to gain loyalty
local food = SpawnPrefab("cave_banana")
merm.components.trader:AcceptItem(food, inst)

-- Check loyalty status
local loyalty_percent = merm.components.follower:GetLoyaltyPercent()

Dependencies & tags​

Components used: eater, sleeper, named, health, combat, lootdropper, inventory, follower, mermcandidate, timer, trader, talker, locomotor, embarker, drownable, foodaffinity, planardamage, skilltreeupdater, debuffable, childspawner, entitytracker, equippable, edible, homeseeker, leader

Tags added/used: character, merm, wet, merm_npc, _named, mermguard, guard, shadowminion, shadow_aligned, lunarminion, lunar_aligned, NPC_contestant

Properties​

No public properties are exposed at the prefab level.

Main functions​

dohiremerms(inst, giver, item)​

  • Description: Handles the core hiring logic when a valid item is given to a Merm. It sets maximum loyalty time, adds loyalty based on food value, updates royal bonuses (if a King is present), and may hire additional nearby Merms if the initial hire succeeds.
  • Parameters:
    inst (Entity) - The Merm instance receiving the item.
    giver (Entity) - The entity giving the item (typically a player).
    item (Entity) - The item being offered (typically food or a fish).
  • Returns: Nothing.
  • Error states: No explicit error returns; logic checks are made internally to prevent double-hiring and ensures the target is not a Merm King candidate.

UpdateDamageAndHealth(inst)​

  • Description: Dynamically recalculates and applies the Merm's damage and health based on world state (e.g., presence of a Merm King) and minion type (regular, guard, lunar).
  • Parameters:
    inst (Entity) - The Merm instance to update.
  • Returns: Nothing.

RoyalUpgrade(inst)​

  • Description: Increases the Merm's scale and updates combat parameters when a Merm King is present in the world.
  • Parameters:
    inst (Entity) - The Merm instance to upgrade.
  • Returns: Nothing.
  • Error states: Early exit if the Merm is dead.

RoyalDowngrade(inst)​

  • Description: Reverts Merm scale and combat stats when the Merm King is no longer present.
  • Parameters:
    inst (Entity) - The Merm instance to downgrade.
  • Returns: Nothing.
  • Error states: Early exit if the Merm is dead.

RoyalGuardUpgrade(inst)​

  • Description: For Merm Guards only. Upgrades the guard's build animation and scale to reflect royal status.
  • Parameters:
    inst (Entity) - The Merm Guard instance to upgrade.
  • Returns: Nothing.
  • Error states: Early exit if the Merm Guard is dead.

RoyalGuardDowngrade(inst)​

  • Description: For Merm Guards only. Downgrades the guard's build animation and scale when the Merm King is absent.
  • Parameters:
    inst (Entity) - The Merm Guard instance to downgrade.
  • Returns: Nothing.
  • Error states: Early exit if the Merm Guard is dead.

DoLunarMutation(inst)​

  • Description: Transforms a standard Merm into a Lunar Merm, transferring health, inventory, and loyalty state. Used when a Lunar Merm consumes Moon Glass.
  • Parameters:
    inst (Entity) - The base Merm to mutate.
  • Returns: lunarmerm (Entity) - The newly spawned Lunar Merm prefab instance.
  • Error states: If inst is dead, returns nil without mutation.

DoLunarRevert(inst)​

  • Description: Reverts a Lunar Merm back to its base form (or Merm Guard variant) upon losing its leader.
  • Parameters:
    inst (Entity) - The Lunar Merm to revert.
  • Returns: merm (Entity) - The newly spawned base Merm instance.
  • Error states: If inst is dead or already reverting, returns nil.

spawn_shadow_merm(inst)​

  • Description: Spawns a Shadow Merm when a Shadow-aligned character kills a Merm while the "Shadow Allegiance" skill is active.
  • Parameters:
    inst (Entity) - The Merm that just died.
  • Returns: Nothing.

TestForLunarMutation(inst, item)​

  • Description: Checks if a given item is Moon Glass and triggers Lunar Mutation if so.
  • Parameters:
    inst (Entity) - The Merm instance.
    item (Entity) - The item being processed.
  • Returns: Nothing.

GetOtherMerms(inst, radius, maxcount, giver)​

  • Description: Finds up to maxcount nearby Merms, prioritizing those with low/no loyalty. Used to hire multiple Merms simultaneously when feeding one.
  • Parameters:
    inst (Entity) - The reference Merm (usually the one being fed).
    radius (number) - Search radius.
    maxcount (number) - Maximum number of Merms to return.
    giver (Entity) - The entity giving the item, used for alignment checks.
  • Returns: merms_valid (table of Entities) - Sorted list of eligible Merms.

Events & listeners​

  • Listens to:
    attacked, attackdodged, suggest_tree_target, entitysleep, entitywake, loseloyalty, stopfollowing, gainloyalty, startfollowing, droppedtarget, newcombattarget, itemget, unequip, equip, timerdone, onmermkingcreated_anywhere, onmermkingdestroyed_anywhere, onattackother, oneat, planarbuffeddirty, loseloyalty (shadow-specific).
  • Pushes:
    cheer, disapproval, makefriend, mutated, demutated, detachchild, shadowmerm_spawn, onmermkingcreated, onmermkingdestroyed, onwakeup, dropitem.