Here is the formula for losing Rage points: Rage_Points_Lost = 1200 * Damage_Absorbed / Stack_Max_HP In simpler terms: Number of Rage points lost = 1200 * Damage Absorbed / Unit Health of the stack. Example: With the base ability, 50% of damage is absorbed. An orc stack is hit for 1000 damage, and the total health of all creatures in the stack is 1000. We get 1200 * 500 (50% of 1000) / 1000 = 600 Rage points lost. In version 3.0 of the game, the formula was slightly different: Rage points lost = 1100 * Damage Absorbed / Unit Health of the stack. The percentage of damage absorption was also changed: 3.1 - 3.0 50 - 50 55 - 60 60 - 70 65 - 80. Honestly, I don't see any changes here that would significantly affect the loss of Rage points.