AN: This is a basic history of the God of the Bible from Highschool DxD. Since there is not much information or background on him or specific subjects this will be the history used in any DxD fanfiction I make regular or crossover unless specifically stated otherwise. Please enjoy.
BIBLICAL HISTORY
+50,000 BC: Yahweh creates Heaven as his domain in an area of the higher plains of existence and fills it with powerful beings he names Angels. It is a paradise with no war or conflict, however unknown to the angels Yahweh also finishes another project on one of the lower plains. Creating a connection between Heaven and a location on the lower plain called Earth he called The Garden of Eden, he created a being called Man of which the first was named Adam. The second he called Woman whom he named Lilith and hid in the garden to surprise Adam with.
But the Earth was not safe, Demons. Denizens of the lower plains of existence, mindless beasts of pure destruction and chaos who want nothing more to destroy everything they can reach. Wary of an attack on the Garden of Eden and through it Heaven, Yahweh assigned four of his Seraphim to monitor the gateway between the Earth and the Lower Plains. Lucifer, Leviathan, Beelzebub and Asmodeus. But soon after contact was lost with the four Seraphim, Yahweh himself led a force of additional Seraphim including the likes of Michael and Gabriel to discover what became of their brethren…and discovered a nightmare.
The four Seraphim, filled and twisted with massive amounts of demonic energy, attacked Yahweh and his Angels. Though they were no match for Yahweh himself the Seraphim with him, while powerful, had never lifted their hands to attack once in their lives. Several died in a split second, horrified but unwilling to kill his own creations, Yahweh used his power to banish the four back down into the Underworld and then placed powerful seals over the entrance to prevent anything from using the path again. Cursing himself for not simply doing so to begin with, but knowing that with the primary connection gone the Demons and now his 4 lost Seraphim would try and find lesser unknown gates to reach the Earth once again.
He was right to fear, driven so far past insane that they arrived back to a new form of sanity, the four X-Seraphim had lost their pure white wings for 12 pure black bat like wings. They had become the first Devils, a very different breed from the Demons of the underworld. With their Holy power turned Demonic and amplified even higher the four now Satans turned on the Demons of the Underworld. Despite how powerful they were, how destructive, how chaotic, the Demons had no actual minds, no intelligence to speak of. Because of this glaring weakness the four Satans waged a long bloody war on the Demons, honing their fighting abilities and Demonic powers, during this time most Demons were destroyed.
Some few were driven so deep into the underworld that they were never heard from again, but some fewer were captured by the four and experimented on. Of those captured most also died in the end, but 72 Greater Demons, 432 Great Demons 2,592 Demons and 15,552 Lesser Demons were all successfully transformed from Demons into Devils. Though they experienced between 20 and 40 percent power reduction, the four satans considered their twisted intelligence a fair trade off. But while they now had appreciable numbers a way to increase them without more Demons they did not.
Lucifer, considered the most powerful of the four, sought a way to correct this. Finding a lesser known passage back to the Earth Lucifer infiltrated The Garden of Eden. There Yahweh had introduced Adam to Lilith and though they were friendly with each other nothing had happened between them yet. Lucifer waited until Lilith was alone and then appeared before her as a man more handsome than Adam and mysterious tempting her to come to him, by the time Yahweh noticed his lost Angel's power it was too late. Lucifer captured Lilith and whisked her away into the underworld, there using the same powers they had used on the Demons the four Satans Reincarnated Lilith into a Devil, the first Human to become one. Becoming Lucifer's bride and eventually the mother of the first born Devil, an aspect was created from her power and given to Satans, Ultimate, Top and Mid Class Devils allowing them to also reproduce naturally if slowly. While the Low class Devils would only receive the aspect after proving themselves loyal and powerful enough to deserve reproduction.
During the kidnapping, Yahweh attempted to enter the Underworld to rescue Lilith, only to be met with the newly created Devils and forced to retreat. Despite the setback Yahweh was determined to see Humanity thrive and so He created Eve from Adam's rib and unlike before Adam responded to her. At the same time, fearing that more of His Angels could end up like the four He lost Yahweh placed a binding edict on the Angels. Should any Angel become corrupted by any of the Seven Sins and fall down the path toward evil and chaos they would Fall from Heaven losing their connection to both it and Him and be banished to the Underworld. At the time all Angels agreed that this was for the best and none Fell for centuries after the binding was created.
What would follow was a dangerous game of cat and mouse, Devils would breach into the mortal world and Angels would fight them off forcing them back. All the while Adam and Eve lived in the Garden of Eden though no children came to them yet they were happy together but it was not to last, Samael one of their Angelic guards unknowingly had his mind poisoned by an unknown source and tempted the two into eating the Fruit of Knowledge from the Tree in the Garden. This introduced Sin into the Humans and forced Yahweh to banished them from the Garden for fear that their sin would lead Chaos into heaven, after which the garden was cut off from the Earth.
Furthermore, Samael became the first Fallen Angel and the most unique and whatever poison was inside of him mutated him into a Fallen Angel Dragon hybrid, this caused Yahweh to suspect one of the Evil Dragons or perhaps even Ophis or Great Red himself to be responsible but He had no proof. Out of the Garden Adam and Even had children and Humanity began to grow but the threat of the Devils was constant so Heaven spent the majority of its time defending the infant race from destruction at the hands of the Devils.
This led to two things, first Angels were sent to Earth to watch over Humanity and protect them. But many of those Angels began to have certain thoughts living among the Humans, Azazel for instance wished for Humanity to be better protected against outside threats and so taught them the arts of war and weapons. In disobeying Yahweh however and interfering with the evolution of Humanity Azazel was the first to truly Fall as it would be come to known, many other Angels would Fall for similar reason almost all of them the ones with the greatest contact with Humanity. At the time the idea that any Angel would disobey an order from Yahweh was attributed to corruption from sin leading to Chaos. It would not be till long after that another option was considered.
The second thing was the arrival or birth of Skyfathers and Skymothers, some born from Gaia the embodiment of the Earth itself as a sort of self-defense reaction others came from various areas of the higher dimensions like the titans and primordials. But they all came for a similar reason, prayer, unlike Yahweh, Ophis, Great Red and Trihexa who were concepts given form these other Gods needed an outside source of power to grow. The prayer and faith of human souls was a vibrant and unlimited source they could not resist.
Yahweh was understandably upset but at first was too busy defending against the Devils and the Underworld to properly respond, however when the first primitive group of Skyfathers and Skymothers went so far as to actually consume human souls instead of simply accepting the power of their prayers He reacted by destroying them personally in single combat. Yahweh's power was his own and he did not require Humanity to pray to him, he didn't create them only to have them sing his own praises after all, when the second and third primitive pantheon met the same fate as the first when they dared consume human souls like a Devil would the rest paused to speak with Yahweh.
They came forth with a deal, so long as Yahweh left them be and did not attack them they would not consume Human souls and would only take energy from freely given prayer to build their realms. However, if he decided to attack the rest of them they would be forced to unite against Him and Heaven to attack. Yahweh knew that even together the primitive Pantheons could not defeat Heaven and Him but they could do enough to distract him to let the Underworld and Devils spill over onto Earth and possibly into Heaven itself. Hating the necessity of it Yahweh agreed and thus most of the Pantheons that would become known in the modern age were born. Most abided by the contract and actually developed friendly relations with Heaven, others faded over time or left for various reasons on their own. Two broke the treaty with Heaven and Yahweh himself descended upon them in fury wiping them from existence.
All this time however the Devils had been slowly growing in power and fortifying the Underworld against invasion leading to a stalemate between the Angels and Devils. Things would come to a head when the four original Satans concocted a plan to finally turn things to their side. They traveled to the deepest parts of the Underworld to find Trihexa where it slumbered and attempted to rouse it, sensing his brother awakening Yahweh panicked. Though he hated the idea of interfering in the lives of Humans like the Pantheons and his Fallen did Yahweh knew he would need an edge against Trihexa and Humanity would need more power to survive. The sacred gear system was the first line of defense, but it was rushed and would be later revealed to have numerous bug within it. Second was the birth of a mortal Avatar of Himself named Jesus whose goals were to begin a religion in His name thus giving Him access to power form Humanity through their prayers like the Pantheons but also to die for Humanity in sacrifice. While humanity would see this as dying for their sins in reality it was a ritual to give Humans the ability to wield Holy powers to protect themselves so long as they were faithful to Him.
With those protections in place Yahweh journeyed into the Underworld to confront Trihexa and sealed it away, but at the cost of a large majority of His power. The Devils expecting this attacked in mass but Yahweh was no fool and a defensive WMD know as Judgement struck from Heaven into the Underworld upper levels scouring the land and destroying all large bodies of water killing a large portion of the Devil's population in the process, mostly among the older and more powerful generations. Weakened from sealing but confident in victory Yahweh confronted his four fallen Seraphs on the boarder between the Earth and Underworld but the Four Great Satans mad with the need for vengeance attacked with no thought for their own lives, as a result all five perished in the battle.
The year was 0027 A.D.