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Stealth & Light

Arx has a stealth system but not a stealth build. The numbers make that unambiguous.

The visibility check

An NPC sees the player when all of these hold:

  1. the player is inside a ±110° vision cone from the NPC's head, and
  2. there is line of sight (or the trace lands within 25 units), and
  3. any one of: ambient light at the player's position > 15 + Stealth × 0.1, or the player carries a lit torch, or the player is within 200 units.

Transitions fire DETECTPLAYER / UNDETECTPLAYER script events, which is how individual NPCs implement their own reactions.

Why the torch wins

Max Stealth (100) moves the light threshold from 15 to 25 — a 10-unit shift on a scale where carrying a torch is an automatic detection regardless of value. A fully specced stealth character holding a torch is exactly as visible as a naked one. So the real stealth verb is Douse (or dropping the torch and navigating blind, or Magic Sight, or Invisibility), not the Stealth skill.

That is a genuinely elegant outcome if you read it as intended: light is a resource the player manages physically, and the skill is only a modifier on it. It is a frustrating one if you read it as an RPG progression promise, because 100 points spent on Stealth buy less than one torch put out. The interface makes no attempt to communicate which reading is correct.

The 200-unit proximity clause matters too: there is no "sneak past someone in a corridor" play. Close range is unconditional detection. Arx's stealth is about route choice and darkness, not about hugging walls.

Sound

Two fixed radii, no skill modifier:

  • footsteps: 600 units
  • dropped/thrown items: 800 units

Distance is passed to the NPC's HEAR script event, so reaction is content-authored per creature. Throwing an object to pull a guard is therefore possible wherever a designer wrote the response — a systemic affordance with hand-authored coverage, which is exactly the profile of the whole game.

The one hard payoff

Stealth's other job is the backstab roll: Stealth × 0.5 % for ×1.5 damage, only against enemies flagged to allow it. See Combat. Even at 100 Stealth that is a 50% chance on permitted targets — a damage-variance perk, not an assassination system.

Touchpoints

  • → Magic & Runes: Ignit and Douse are the strongest stealth tools in the game; Invisibility skips the check
  • → Combat: backstab permission
  • → World & Level Structure: because darkness is the stealth stat, torch placement is enemy placement
  • → Simulation & Interaction: torches are physical carried objects, droppable and extinguishable

What breaks if you remove it

The light economy is load-bearing for atmosphere and for the underground fiction. The Stealth skill could be deleted with almost no mechanical loss — which is itself the finding.