Unbridled Rage

Unbridled Rage is an ultimate passive talent in the Warlord (Red) tree. It cannot be taken with Walking Arsenal.

In-game
Damage boost is multiplicative, and applies to all Fury skills:, , Upheaval, and. The double cost applies to the base cost of the skill, before any relevant modifiers.

Since the total damage the Barbarian can dish out at once is limited by the maximum anyway, the overall short-term damage increase is roughly 15%.