Bleeding occurs as a result of a physical attack on the body. This attack could happen from any number of sources including, but not limited to adventurers, denizens and creatures, and finding oneself set ablaze, such as after walking through a burning forest.
Bleeding represents a small loss of health over time. As the body heals itself bleeding naturally reduces to zero. This process is greatly speeded by a moss tattoo or clotting (a Survival ability).
Certain attack strategies or special weapons actually increase or capitalise on victim bleeding, such as sanguine tempering by an Alchemist, multislash of a Blademaster, or an attack using Bloodletter.