This is a Talent that can be chosen when a character reaches level two. It activates the person's Soul’s Fire allowing them to withstand normally fatal wounds for a short period of time. For some reason, Brendel was able to survive after the first activation of his Unyielding skill, despite the fact he did not receive any healing beyond a simple Bandage.
Unlike in the game world, Brendel seems to be able to defy the rule about losing his consciousness after the five minutes, however he seemed muddle-headed and struggled to stay focused.
In the game it allowed a player to resist becoming unconscious from bleeding for five minutes, and not die from any physical attacks for thirty minutes. In order to survive, the player would definitely be healed within those time limits.
The players would be completely unaffected by any negative side-effects for those five minutes. However, once the time was up, no matter how fine they felt, they would immediately collapse onto the ground.