Enemies & AI

MSB Enemy part (model, NpcParam row, NpcThinkParam row)
  NpcParam      → HP, capsule, turn speed, display masks, whose clips it borrows, its attack rows
  NpcThinkParam → which Lua battle goal, eye range and angles, smell, how far it chases
  AI (Lua 5.0)  → weighted roll of an "act" by distance → subgoals (approach, attack, combo, strafe, back off, turn)
                → requests an action id each tick (3000 = W_Attack3000)
  NPC script (HKS common_npc) → behaviour events → shared graph c9997 → clip a00X_NNNNNN
  clip TAE      → AI cancel windows, turn speed, AttackBehavior, Bullet

1Anatomy of a hollow

m40 places 41 c1430, more than any other model. Their NpcParam rows differ in HP (59-183) and display masks; all share behaviorVariationId 11000, turnVellocity 180, hitRadius 0.4, and no poise at all. Four kinds:

Borrowed clips and a shared graph

• c1430.anibnd holds only a skeleton. The clips and TAE are the Hollow Soldier's (c1100), named by NpcParam's normalChangeAnimChrId, and the skeletons match bone for bone.
• c1100's own graph is a stub. The states are in c9997.hkx, the common humanoid-enemy graph (2,329 clip generators).
• Every selector picks a clip prefix a000-a005 by the SpEffect's animIdOffset ÷ 1,000,000. The prefixes hold only what differs: a002 (crossbow) is just its shots; anything missing falls back to a000 guess.

2The NPC script

c1100's own HKS handles only event animations. The logic is the shared common_npc.hks data:

• AI requests arrive as an action id, env(106): 3000-4499 → W_Attack<id>, 9910 raise the guard, 6000-6109 steps, 700-799 unique idles.
• Movement by MoveAngle: within ±45° walk forward (run above level 0.75), 45-135° right, beyond 135° back, else left. Turns of 45° or more play ±90° or ±180° clips.
• Damage by level: 1 small, 2 middle, 3 large… Any level above 0 calls Replanning(): getting hit makes the AI throw away its plan.

Inside an attack clip, the AI may cut in only in its windows: TAE flags 23 "Cancel – AI Combo Attack", 86 "AI Attack", 78 "AI Movement", 79 "AI Dodge". In a000_003000 (3.37 s): 23 from 1.17 s, 79 and 86 from 1.9 s, 78 from 2.07 s. TAE 224 sets the turn speed through the swing (90, 120, 0, 0, 45, 0 °/s), which is how an attack aims itself.

3The battle AI: Lua goals and weighted dice

The AI scripts are Lua 5.0 bytecode (not HKS): script/aicommon.luabnd (209 shared goals and helpers) and script/m40_00_00_00.luabnd (the area's battle goals). NpcThinkParam.battleGoalId names the file. Goals form a stack: a goal's Activate pushes subgoals, its Update reports success when they're done, and the battle goal replans every time its subgoals run out. Interrupt handlers can clear them early.

Battle goal 110005, the sword hollow

If the target is more than 60° off its front, it turns. Otherwise it weighs its acts by distance:

Each act first approaches to its reach less its own radius: it runs when at least reach + 10 m away (or half the time at reach + 1), giving up after 4 s walking or 8 s running. The after-attack act then rolls again by distance: strafe 2.5-4.5 s at 30-45°, back off 2.5-4.5 m, or run back in.

Attack goals are C++ (GOAL_COMMON_CommonAttack). The Lua wrappers show only their parameters: success distance, turn time, front angle.

4Noticing you

The Lua only reads states that C++ sets (IsBattleState, IsFindState, IsCautionState). The inputs are in the data:

• Sight: eye_dist 15 m, eye_angY 30° (a half-angle), eye_angX 25°. Crossbow rows see 30 m at 60°. Gundyr sees 65 m, 120° each way.
• Hearing: the player's clips fire TAE 237 SpawnAISound with an AiSoundParam radius: walk 0.4 m, run 5 m, dash and roll 7 m, landings 1-7 m. The hollows' own clips fire none, so fighting one doesn't draw the others.
• Smell: nose_dist, all round. One hollow is an ambusher: eyes 2 m, nose 1 m.
• ear_dist is mislabelled: 0 in 698 of 749 rows, else 9910, the guard request. It's on exactly the shield users.

5How DS3 makes enemies customisable

Almost nothing about an enemy is hard-coded. A designer composes it from data:

6Iudex Gundyr

His AI: phase 1 acts by side and distance (within 3 m on his right: 55 % act 4, 45 % act 5), with cool-downs (3000 not again for 10 s). Phase 2 adds rolls back and to the side after attacks. Small and middle hits don't flinch him: his only damage clips are Large. After a death, he rises again when you come back through the courtyard's gateway (region 4002800, a 6 × 3.8 × 6 m box 36 m from him), not when you walk up to him.