[They created a monster called the Blood Nightmare.
It was a piece of meat that was as huge as a mountain and was directly cut off from the Mother of the Abyss.
Every once in a while.
The Blood Nightmare would automatically expel the excess pus and blood from its body to its surroundings.
People or things that were washed by pus and blood would degenerate into demons.
In the beginning.
The Blood Nightmare was a tool in the hands of other Demon Overlords.
However, after a certain day.
The Blood Nightmare gained self-awareness. He severely injured the Demon Lords who tried to control him and occupied the 49th level of the Abyss alone, becoming a terrifying Abyssal monster.
The Blood Nightmare Fallen Angel had an unusual obsession. He was particularly keen on tricking angels into drinking his blood and transforming them into powerful Fallen Angels.
However, angels were relatively rare in the Abyss.
