Nerves of Steel

Nerves of Steel is a passive skill in Diablo III, unlocked at character level 13.

The 60-seconds cooldown may not be reduced by normal means, only being removed if the Barbarian dies.

For obvious reasons, this skill is considered mandatory for Hardcore characters.

Development
Originally, this skill was increasing the Barbarian's Armor by half of their total Vitality. In patch 2.2.0, it was replaced with a life-saving mechanic, making Barbarians the last class to gain one.