Prehistory (It's quite long, but just in case you interested) also it's all made up so don't take any seriousness please ...
If I told you that humans were originally created by both God and Satan would you believe me? "It's impossible!" I imagine some would say but it's very much realistic if you see it from my point of view. See everything needs a balance in order to exist safely, like a pendulum both sides has to have something in order to be stable. We human can be both angelic and demonic, we are sort of like the origins of every living things even gods and deities are just at the same position we are but levels higher. Not saying that we could all someday evolve to such higher beings, but it's not impossible. In fact nothing is impossible, because the existence of something is already a flaw in the nothingness thus taking out the possibilities of "Perfect" or "Pure". Those are only ideologies, so are our view and beliefs, the truth is always somewhere flaw. As history goes by like light it distorts in majority's view, we forget to the point of mistakes becoming right. So once again upon a time there was. In the beginning there was Great Red and Ophis, God and Satan. They where all bored so they created many things with each other which includes everything now and those that will ever exist. All seemed fine until they created life and the humans. To having a simple soul and container is fine (body) is fine but the humans where much more complicated creature once they began to evolve unexpectedly. They developed such emotions as love and hate, and began being self-aware and opinioning. Like it was new fashion everything was changed by this new thing, even Satan and God. Eventually the humans began to be aware of higher powers like God and Satan, which obviously they favored God more because they thought that God must be good and that Satan must be bad. Which wasn't true until they made it true. Satan wasn't pleased but he wasn't hateful either. He was kind of sad so he began to find company and help the humans. Being helpful? Yes but humans where sort of too dump to acknowledge, so they shunned him avoiding him like plague. Poor Satan was sad so he went to find God to ask why only to see him being loved so much by the people. It's what he wanted, but as he moves close people treat him differently and eventually begin attacking him as they thought he would hurt their beloved God. God wasn't aware and Satan didn't understand why so everything was in confusion. It was still peacefully till one day a truly evil man in the name of Lucifer decided to manipulate this dense deity. He told him lies amongst lies and angered him into becoming a demon lord, creating the first of devils to corrupted the humans that was his enemies he thought. God and Great Red created the System so human could defend themselves somehow against the devils with their Exorcism and Sacred Gear. However it wasn't enough as devils where clearly too power compared to humans and humans can fallen to devils or be resurrected as one against their will. So now God also viewed Satan as a enemy as he seems somehow un-rightful and out of control. He created the 7 Archangels and angels to fight against Satan's 7 Maous and devils. They fought for a long time ... However one day Lucifer betrayed Satan and Helel betrayed God that changed everything. They both where quite similar and powerful but mostly ambitious. Through some type of ritual they merged together creating a being almost as strong as god but a few levels below. Still that was enough to cause trouble. God and Satan grew up and matured through the endless bloodshed in the battles against each other, as veteran they noticed something fishy was going to occur so they halted the war against each other. They made changes to their systems and united their unit in the armies to investigate in the world. As if they where blind a lot has changed that doesn't mean like destruction they caused. There where new races, new gods, and new powers that didn't originate from the 4 originals of this world. If Satan, God, Great Red, and Ophis were a coordinate plane then that means that something from somewhere else is taking place here. It turned out to be 666 from the other world and many of the deities from there too. While the deities were escaping here from the other world because it was chaos and cruel, Trihexa or 666 the overlord there noticed. It became fascinated with the new discovery of this world and plans to visit in the most unpleasant way of course as a overlord (Invasion). The one lead his army was non other than the monster of both angels and devils Lucifer/Helel, it was also it who introduced Trihexa this world he is about to invade. Great Red and Ophis teamed up with Satan and God to defend mankind against Trihexa's terror. It was the most gruesome war ever to be fought, both sides with lots of casualties. But in the end This world won. Trihexa was strong that even Great Red and Ophis feared it, he could easily beat one of them and even manage both. After his army was demolished and Lucifer/Helel betrayed him by stealing some of his power he was cornered up by Satan, God, and a weakened Great Red (Ophis was too weaken to fight so she retreated). With a furious battle and ending in a flash of glory his conscious was sealed by God. Finally peace was here after so long as they thought. Great Red returned to the Dimension Gap, Ophis was left wondering around to Recover from her injuries, God created Heaven the home of angels, fixed his system (which resulted in fallen angels), and apologized to Satan, Satan created Hell(It's not like how most people would describe it) the home of devils, fixed his system, gave most of his power away forming the 72 clans, and apologized to god too. Pax Romana, well it was peaceful. Lucifer/Helel wasn't making any moves for a while, but he was we know it, was no more. As a Devil/Angel hybrid that stole power from Trihexa he gained a fearful ability to transform into anybody, a monster with many faces and identities. He sparked another war as he disguised as Satan and to assassinate God. The angels were mad beginning to attack and killing the devils, which had no idea what is happening. The devils thought it was war so it was and punched back. God wasn't dead but gravely wounded and Satan was confused, both were not in shape for another war or could lead a their creations again. So both of them disappeared entering a state of solitude once again. God went to find Satan when he has recovered reasonable enough in secret. They sort the matter out calmly even though there was a war being fought by their children (angels and devils, humans against other humans), it has never occur that someone could have such a ability, yet it has also not occur there was Trihexa right? Soon they hypothesized the culprit to be the monster of angels and devils Lucifer/Helel. They had to lure him out somehow so the best way was to pay along with the tricksters game and act dumbly. Even though it wasn't the least in bloodshed it was still the most efficient and safe way to go about finishing this troublesome being. God and Satan clashed once again however for a different reason and reason now. The plan was for them to seal off most of their power that they have left and act powerless in their last duel so that Lucifer/Helel would appear to finished them both off for that is his nature. The plan failed miserably however, ending up with Satan and God both kill along with everyone totally believe that they lost their precious leader, which fumed the war to a whole new scale and the fallen angels stepping in too because it was even disturbing them. However still they manage to drag Lucifer/Helel down with them because their deaths alerted Great Red who showed up to finish the monster. After they died, God choose to go to the realm of the faded and leave the system to the hands of the Angels and humans to the fate of themselves, he believed in them to the very last of his moment before he finally rest. Satan was a bit disappointed and unhappy about dying, as there were still lots of things he wanted to do and experience, so he decided to reincarnate, however there is always some problem eh? Lucifer/Helel along with the rest of Trihexa's powers was sealed into 6 sacred gears called "The Forbidden Lost Keys", they are top-tier sacred gears that don't actually belong in the system.
Character Alpha
Name: Issei Walker Hyoudou
Birthday: February 14 Aquarius (Also it's Valentine Day)
Age: 15
Height: 175cm
Weight: 55kg
Status: Alive
Gender: Male
Species: Human
Blood Type: AB+
Home Country: Japan or United Kingdom
Partner: Satan
Affiliation: Walker Family
Occupation: Student, Exorcist, Magician
Ability and Sacred Gear: Secret/Classified/Unknown
Relative:
Allen Walker (Ancestor)
Road Kamelot (Ancestor)
Unnamed Deceased Parents
Nobuna Walker Hyoudou (Adopted Sister)
Kiritsugu Emiya (Distant Relative Uncle/Godfather)
Character Beta
Name: Nobuna Walker Hyoudou
Birthday: May 11 Taurus
Age: 17
Height: 170cm
Weight: 45kg
Status: Alive
Gender: Female
Species: Human
Blood Type: O+
Home Country: Japan
Affiliation: Walker Family
Occupation: Student
Ability and Sacred Gear: Booster Gear(Unawakened Form)
Relative:
Unnamed Deceased Foster Parents
Issei Walker Hyoudou (Adopted Brother)
Kiritsugu Emiya (Distant Relative Foster Uncle/Godfather)
Top 10 Strongest Listing
Red (Common Sense)
(Before Losing Her Power)
of Bible (In His Prime)
Satan (Before Giving Away His Powers)
(God of Destruction)
(Hindu God of The Heavens)
/Helel (Monster or Angel and Devil, Vessel of Trihexa, Traitor)
(In His Young Days)
(He Owns The Dead)
(Slayer of Balor)
Note: The House of Lucifer still exist via sperm bank. Satan despite how much he loathed Lucifers betrayal still had some respect in him. Respect to the Previous Sane Lucifer not the Monster of Angel and Devil. Lucifer/Helel might also be Samuel The Dragon Eater. Or not
Author's Note:
Sorry for not updating on my other two fanfics but hmm, I sort ran out of ideas and was really busy because now that, I entered high school (boo no more middle school free time and careless grades) I've started this story out of curiosity, so don't expect much please. Also I've started actually reading the Light Novel of this anime, which is really good. Ahh why is English so hard, even translations are more cooler.