Endurance charges are one of the three charge types. They are associated with strength and represent a temporary increase to the ability to endure pain during combat. They are visualized as glowing red orbs surrounding the character.
The physical damage reduction is effective against hits and non-hits such as bleeding. When reducing damage from hits, it stacks with the damage reduction from armour, so that they are both applied at the same time.
The effects of endurance charges are much more significant on monsters.