Regenerates 5 HP every round, making it difficult to kill the hero through the last breath mechanic.
Two killing blows would have to be dealt in a single round, or by reaching the hardcoded limit to how many times last breath can be activated. The latter often happens on the King in Gold fight which is the only which lasts long enough.
It is a keystone to high defense builds. Each regenerated hitpoints values scales with the effectiveness of your resistances, almost fully regenerating strikes from knights guarding the King in Gold with a full hero armor set.