From DEFAULT.ini

[Difficulty]
; -- THIEF 3
;
; AI visual acuity multiplier - how well AIs can see
Difficulty_AIVisual_Mult_Easy=0.9
Difficulty_AIVisual_Mult_Normal=1.0
Difficulty_AIVisual_Mult_Hard=1.15
Difficulty_AIVisual_Mult_Expert=1.2
;
; AI auditory acuity multiplier - how well AIs can hear
Difficulty_AIAudio_Mult_Easy=0.8
Difficulty_AIAudio_Mult_Normal=1.0
Difficulty_AIAudio_Mult_Hard=1.03
Difficulty_AIAudio_Mult_Expert=1.13
;
; AI tactile acuity multiplier - how well AIs can feel
Difficulty_AITactile_Mult_Easy=1.0
Difficulty_AITactile_Mult_Normal=1.0
Difficulty_AITactile_Mult_Hard=1.0
Difficulty_AITactile_Mult_Expert=1.0
;
; AI hitpoints multiplier - all AI starting hitpoints will be scaled by this
Difficulty_AIHitPoints_Mult_Easy=0.75
Difficulty_AIHitPoints_Mult_Normal=1.0
Difficulty_AIHitPoints_Mult_Hard=1.2
Difficulty_AIHitPoints_Mult_Expert=1.3
;
; AI combat speed multiplier - all AI combat animations are scaled by this
Difficulty_AICombatSpeed_Mult_Easy=1.0
Difficulty_AICombatSpeed_Mult_Normal=1.0
Difficulty_AICombatSpeed_Mult_Hard=1.1
Difficulty_AICombatSpeed_Mult_Expert=1.2
;
; AI-to-player damage multiplier - all damage applied to the player by the AI is scaled by this
Difficulty_AIToPlayerDamage_Mult_Easy=0.0
Difficulty_AIToPlayerDamage_Mult_Normal=0.0
Difficulty_AIToPlayerDamage_Mult_Hard=0.0
Difficulty_AIToPlayerDamage_Mult_Expert=0.0