When Lucy was first born from the pride of Adam, she assisted in the spawn of the other Great Demon Lords.
Belfygg, the King of Sloth, was born from the lack of ambition in Adam and Eve.
Asmodia, the Queen of Lust, was born from their desire to procreate.
And finally, from this first set, Belzye was born from Eve's consumption of the Apple in the Garden of Eden.
From this, bore Setanta, the King of Wrath.
After generations of men, women, and children... Levi and Maeon were born, Envy and Greed, together. They were twins, and always would be.
Thus, the Seven Great Demon Lords bore fruit from the birth of Humanity.
From their procreation, came the Lesser Demon Lords. Who they themselves would later birth their own organizations in the form of Cardinals, Templars, and Pawns.
Pawns, known as Daemons, are the demonic influences frequently commented upon by religious organizations.
From this bore the Demonic Possession, and in rare cases, Resurrection system. The Demonic Possession System was birthed to establish a balance between the possessor and host during the possession of/by a Demon Lord. This was regulation, regardless of circumstance. In-order to keep this balance, even if one individual of this possession should die, the system will automatically update to keep both alive... The Demonic Resurrection System.
The Hierarchy of Demons:
Great Demon Lords
Lesser Demon Lords
Demon Cardinals
Demon Templars
Demon Pawns (Daemons)
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The Order of Birth of the Great Demon Lords
The First Five:
Lucy Fern the Prideful
Belfygg the Lethargic
Asmodia the Lusty
Belzye the Hungry
Setanta, the Beast of Rage
The Twins:
Maeon, the Greedy Bastard
Levi Alveister the Tenth, King of Envy
This, is Demonology 101.