It is unknown how the entity that would come to be known as the Black Moon came into existence. It existed outside of reality and began using its power to petrify and obliterate random sentient beings within the universe every long period of time. However, in the early history of Earth, a man obtained the Counterbalance to the Black Moon, granting him immortality and immunity to the Black Moon's power. The man tried to fight the Black Moon for thousands of years to no avail and eventually grew too old. Back when humanity was so ancient that they didn't even use names yet, the old man settled in a small village and one day encountered a young boy who witnessed the youngest hunter of the village being killed by the Black Moon. After informing the boy of the Black Moon the old man decided to make the boy his successor in order to keep fighting against the Black Moon and gave him the Counterbalance before he crumbled to dust.
The Black Moon seemingly became an enemy of the Scarlet King and the two began battling out with each other, both of them using their servants as pawns to help them win their fight. The entity once took some knowledge from the Wanderer's Library at some unknown point in the past, causing it to become one the Library's many enemies.
Powers:
-Immediate petrification and obliteration
-Omnilingualism
-Extrasensory perception
-Teleportation
-Immortality
-Nigh-omnipotence
-Interdimensional travel
-Incorporeality
-Power bestowal
-Mind control