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Shadowthrall Hands Brain

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

Overview​

ShadowthrallHandsBrain implements the behavior tree for shadow thrall hands, a boss-minion entity in DST. It coordinates movement and attack timing relative to a home position and a target (either directly assigned via combat component or indirectly via horn entity state). A key feature is turn-based attack sequencing: it avoids overlapping attacks with its teammates (horns and wings) by checking their lastattack timestamps. The brain uses a PriorityNode root to prioritize waiting for attack turns, closing in on targets, and wandering when idle.

Usage example​

local inst = CreateEntity()
inst:AddComponent("entitytracker")
inst:AddComponent("knownlocations")
inst:AddComponent("combat")
inst:AddTag("shadowthrall_hands")
inst.brain = ShadowThrallHandsBrain(inst)
inst.brain:OnStart()

Dependencies & tags​

Components used:

  • combat — retrieves target, checks InCooldown() and TargetIs().
  • entitytracker — fetches related entities (horns).
  • knownlocations — retrieves spawn point for wandering baseline.
    Tags: Checks running and attack state tags via self.inst.sg:HasStateTag().
    Entity relationships: References horns and wings entities via entitytracker, and assumes formation and sg.mem.lastattack properties exist on the instance.

Properties​

PropertyTypeDefault ValueDescription
btBTnil (set in OnStart)Behavior tree instance used to drive AI behavior.
instEntity(inherited from Brain)The entity instance this brain controls.
formationnumber (degrees)nil (external)Optional rotation offset (in degrees) used to compute formation position around target.

Main functions​

OnStart()​

  • Description: Initializes the behavior tree with a hierarchical priority structure. It creates a PriorityNode root with three branches: wait-for-turn logic, combat execution, and wandering — in that order of priority.
  • Parameters: None.
  • Returns: Nothing.
  • Error states: None documented. Assumes GetTarget, GetHome, GetFormationPos functions are valid and entities referenced via entitytracker exist during runtime.

Events & listeners​

  • Pushes:
    • doattack — fired during the combat branch when the entity's turn arrives and it is not currently attacking, passing { target = self.inst.components.combat.target }.
  • Listens to: None. (Event listening is handled internally by components like combat, stategraph, and the behavior tree, not directly on self.inst.)