Co-written by XXAlter and edited by ekaterina016

Chapter 1: The Sins of Our Past

He wished for a world only inhabited by humans, without Demons and Angels, and destroying the throne of the God of Creation. After Metatron's defeat, Nuwa approached and told him what she had hoped when she and Yakumo joined: a world where her creation could live in peace.

Or so she thought.

His victory over Lucifer meant he could finally fulfill her wish. It was the perfect ending, right? Gods and Demons would cease to exist, allowing humanity to finally achieve their liberation, free from all the supernaturals – an ideal world, or so he would've thought. That was, and still is, the main reason why he wanted to fulfill her wish.

"Nahobino, you've proven yourself. Now, strike me down! Kill me! Reclaim the world you want!" Lucifer ordered.

The Nahobino didn't waste a moment. He leaped forth and struck Lucifer with his fabled Murakumo – the tōtsuka Susano'o had used during his fight with Yamato no Orochi – using all the strength he has. The power he had accumulated was enough to kill Lucifer, but not without sacrifices. Some of his Demons had died a painful death, protecting him against Lucifer's full strength and allowing him to prove himself to The Devil.

"At last, the Nahobino defeated me! His power was so gruesome and powerful God had banned it when he was alive.

"Magnificent, my children… With this, the world will indeed be freed."

Those were Lucifer's final words before he died.

"So this is it, then. With what Lucifer has shared with us, the world you created will be everlasting," Aogami said while looking at him. They had been through so much together, so even Aogami was forced to realize what humans are capable of.

"Will it, though, Aogami? Who knows, maybe it will be destroyed again in a hundred or thousand years? You saw what the Demons are capable of doing, saw how much destruction they had caused," Nahobino sighed. The Revelation Aogami had given him when they first arrived at Tokyo Tower reared his doubt. There would always be a higher power. How long would the world he painstakingly created even last? 100 years? 1000 years? The answer was… he didn't know.

"True, unrestricted freedom… born from eons of unending battle. All that's left is to add the final touches."

"Aogami…"

"Young man, I have learned a lot from you… I have learned what it means to be human. I have learned what humans are capable of, despite not possessing any power within themselves. You showed me what Demons didn't know. You showed me what human love is, something Demons and God didn't have.

"You all were a pawn to their game, and maybe Lucifer indeed loved humans. He decided to betray his Father to unchain them. Don't worry – after we've parted ways, our souls are one and the same. All you do will be as I would have done."

"So this is the end of the line, huh?"

"This is our final farewell, young man. It had been an honor serving by your side."

Aogami then extended his arm, just like what he did when they first met. Even though they'd only been partners for a while, he now shares a deep sense of camaraderie between the two of them. The young man took Aogami's arm resolutely and shook it.

With that, it was the end of a long journey for them. The last greeting between comrades marked the end of an era and the beginning of a new one.

Aogami would be no more, and he would get the normalcy he craved so much back then. It was sad to see him go. He would miss him, for sure. Aogami had helped him during his first unfortunate dealings with daemons, Itsukushima, the fairy village, the Demon King, and when he dealt with former Bethel leaders.

Suddenly, the space around him warped and curved, sending Nao's sense into haywire as his mind was still deep in thought. From the outside perspective, it was as if the young man's body slowly distorted and disappeared into a whirling pool.

Moments later, Nao regained his consciousness. He seemed to have arrived at some type of star system, very much similar to humans' own Solar System. In the center of it was a star, but weirdly, it didn't hurt him when he looked at it. Instinctively, he walked towards it, as his hellish memories of the experience in Da'at was suddenly revived in his mind.

He had expected to wake up in a world where all of his friends had survived Da'at; he might regain the normalcy he had before that faithful day. He had expected to finally live in a world where he could finally ask Isonokami out.

Isonokami Tao…

Before Da'at; he only knew her as 'Isonokami' – the girl he was infatuated with since second grade. He wanted to ask her out on a date. When they had been entangled with the supernatural, they had been busy with each other's duty: as a Nahobino and the Bethel's Holy Maiden respectively. She was also trying to help her best friend – Itsukushima Sahori. The poor girl had been bullied badly, forming a pact with the Demon Lahmu.

Lahmu… the reason why he had to kill Itsukushima. The girl looked like she had a damn power trip while killing the bullies. The red-haired girl killed Isonokami – she killed her! He couldn't even forgive her. What's done is done, though – he had failed her. Failed in saving the girl he loved. But the past was the past; he has a new era to look forward to.

He woke up.

He finally woke up.

Checking his surrounding; he noted he was in some sort of public park. The pain in his head took him by surprise, though. It's like someone hit him in the back of his head with a bat.

"Are you okay over there? You look like you've taken a trip to hell…" the voice of a man said while chuckling.

"Wait, what-" He then stood up and looked around. The man was of an average build, looking like he was in his mid-life crisis.

"Hey, uh… what are you doing sleeping there, huh?" The man then asked again.

"I-I don't know…"

"Hmm… What's your name then, young man?" the man asked again, looking worried.

"Kiyoyama, Kiyoyama Nao," Nao replied tiredly. He had finally done it. Create a world where Demons didn't exist. He could finally breathe easily, knowing the threat is no more. "Where am I?" Nao then asked the man.

"Kuoh Public Park, how did you not know?"

'Kuoh? Where in the world is Kuoh?' He thought to himself, before asking, "Kuoh?"

"Kuoh, yeah… Are you okay over there? Could I get you something? Some water, perhaps?"

"I'm fine, I think…" he then replied.

"Oh, man, I thought you were dead. Somehow you ended up here and you're asking me about Kuoh; did you drink alcohol? Kids like you shouldn't be drinking at this age, you know." the middle-aged man chided with an amused tone.

"I'm sorry, sir, but… where is Kuoh exactly?" Nao asked, not really understanding his situation at all. He wasn't the best at geography, so maybe he might've skipped some small towns here and there, he reasoned with himself. "Is there somewhere – like a library – for me to use a computer?"

After receiving directions from the kind man, Nao bid him farewell before making his way through the town. A few minutes later, he arrived at a building with the large, bold letters of 'Kuoh Plaza' engraved on its front. Getting inside, he went to the library and was greeted by a librarian, and after some questions, he was allowed usage of the computers within the facility. Turning the piece of tech on, he was surprised to see the technology of this place is a more primitive one to his previous world. Opening what he assumed to be a web browser, Nao began his investigation.

- …

He tried his damn hardest to find information about the world. He searched for Jouin High School, Prime Minister Koshimizu Hayao, or any resemblance to his old life. The search was, unfortunately, futile. For some reason, they seemed to have vanished… as if they never existed in the first place. 'That's… impossible? Right?' The young man tried to reason with himself.

The current prime minister was someone named 'Shinzo Abe'. Jouin High School was now some public park, and the diet building was different from what he had remembered. In the end, there was no Jouin Highschool, Prime Minister Koshimizu, no Bethel.

No Isokonami…

'Then where the hell am I?' Nao thought to himself. He had been stranded in a world he didn't know. Alone, with nowhere to go, in a city he didn't have an ounce of knowledge about. What happened? Was there a mistake somewhere in his process? Did killing all Demons standing in his way caused this? Once again, he didn't know.

Reality kicked in again. The truth was there to be seen, and he couldn't refute it. He had to accept the new world he'd created, the world he fought tooth-and-nail to bring back… no longer existed. It had been a bitter pill to swallow. One couldn't forget Da'at, a literal hell on earth. The unending fights with Demons, Angels, youkai, and many more mythological creatures. He remembered his first fight against daemons so well – a psychological scar.

Sometimes, he did wonder if Da'at was just a nightmare, a figment of his imagination, or an elaborate dream of some sort. But no… it couldn't be…

Now, he was without a home, money, and identity.

Rummaging his pocket, he found a key and a letter from 'S'. He didn't know who this 'S' was, so he unwrapped the paper and took a good look at it.

"Congratulations, Nahobino. You have put an end to the Cycle of Mandala; I hope to see you in the future. Take the house key; you'll need it.

— S."

He also found an address where his new home seemed to be.

'This is all I got after all I've done for this world?!

'Well, it's better than nothing,' he supposed; life was unfair – when had life ever been fair to him? Or anyone, for that matter. All of his friends didn't get a choice. Two of his friends sought to create a world based on their ideals and beliefs. One other contracted a terminal disease. Isonokami had died trying to save Isukishima, and then it turned out she was the Goddess of Creation.

Life was unfair, indeed.

His failed investigation brought him back to the park, in an attempt to find at least something he missed. And then, his point was proven once more...

"Sorry. You were a threat to us, so we decided to get rid of you early. If you want to hold a grudge, then hate the God who put the Sacred Gear inside you." It was a voice of a woman, he assumed… and 'Sacred Gear'?

"The God who put the Sacred Gear inside you?"

It didn't make any sense….

Lucifer killed God, didn't he?

What's the talk about God and Sacred Gear, then? It makes no sense at all.

'I need to find out what was she is talking about,' he thought.

Yes, he needed to find out what had happened. He did what any other human shouldn't have done: run to the park.

There, he saw her: a Fallen Angel. A mildly shocked expression could be seen on her face, no doubt because of him. But the moment of distraction he created with his appearance wasn't enough, and in the end, he couldn't stop the light spear from piercing the young man in front of him.

"What the hell? How did you…?! WHY?!" A million words were rushing through his head. 'What happened? How could she do that? I thought…' His train of thought never finished, as Raynare created another light spear, and this time, she threw it at him.

Relying on his reflex, Nao instantly stopped, letting the projectile harmlessly strike the ground in front of him, before disappearing into motes of light. "Who are you?! What did you do to him?" He said in a disbelief.

"Oh, him? Well, he had a Sacred Gear. I was ordered by Azazel-sama to kill the brat since he would become a threat to us. And as for who I am… Why should I reveal my name to a lowly creature such as you?" The Fallen replied, laughing maniacally. Two spears… then four, six, eight spears of light appeared in her hands and behind her, all aimed at him.

Nao, feeling a familiar sense of rage creeping up in him, did what no other human could have accomplished in that situation: He dodged. All of them, by a hair's breadth. The Fallen Angel's eyes slightly widened at the sight, before she chalked it up to herself it must have been luck and prepared yet another barrage.

"Hoh… Struggling vermin! This will be interesting… Humans are just so easy to kill; it's getting boring for me. They just stand there, stiff as stone, scared and helpless, unable to comprehend what's going on. It's quite amusing to see someone like you struggling – I wonder how good it'd feel to see your despair when you realize this is all going to be in vain!" Rubbing her thighs together, Raynare's eyes shone madly as she imagined the scenario she had just thought up.

'This bitch is crazy; I gotta get out of here!' He forced himself to get up and started running, hoping to escape her as fast as his leg could carry him.

"AHAHAHAHAHAHA! I TOLD YOU, DIDN'T I? YOU'RE GOING TO DIE HERE!" Raynare laughed wildly, forming another light spear.

Deciding he couldn't run from her, Nao quickly changed his direction back to the crazed Fallen Angel. Tilting his head to the side, he avoided the light spear aimed at it and arrived in front of his enemy, immediately throwing a trained right hook with all his strength, twisting his body to grant the fist even more power with minimum preparatory movement, smashing his knuckle against the raven hair's side.

Raynare knew this boy was something else – something special. She wondered what the Fallen Angels could do if they ever got a hold of the boy. Torture him, perhaps? No, they could take a look and see if he has a Sacred Gear, and then extract it from him, leaving the boy dead.

Enraged at the action of the insect in front of her, Raynare didn't even waste a moment upon contact before landing a devastating kick in the teen's gut, launching him away like a ragdoll. Trickles of blood fall from Nao's mouth, leaving no doubt his internals were damaged from the strike.

He felt like dying – the Fallen confirmed there were Gods and Demons in the world, and without his Nahobino power, he might as well be an ant, confirming the Fallen's degrading thoughts of him.

"Hmph… I just left you for a moment, and you're already this close to death? What would Isonokami say if she sees you right now?"

That voice… He couldn't believe it! After all of this time! 'Aogami…?!'

Staggering, Nao managed to stand up straight, only to see shining spears of light heading straight towards him, each carrying enough power to pierce through a human like a hot knife through butter. That was, if he was still a normal human.

"Are you ready, partner? Just like old times!"

Strength surged through his body; his bruised stomach heals in a blink of an eye. With that renewed strength, he caught the light spear Raynare threw effortlessly.

"HOW?!" She roared, mouth agape. 'No, humans aren't supposed to be strong!' They were weak, just vermins – like that Hyoudou boy she killed. Humans were pathetic creatures her Father had created. Because of that, Father gave humans Sacred Gear to give them a fighting chance against the supernatural. 'Was it a Sacred Gear? No, Azazel-sama didn't mention another Sacred Gear user roaming around in Kuoh…'

"DIE DIE DIE DIE!"

She threw a barrage of attacks, yet he deflected all of them this time, not even bothering to dodge. Raynare had never seen a human like this in her life.

Suddenly, bands of blue light burst out from Nao's body before wrapping around him like a cocoon. It shone brightly before dissipating away, revealing a familiar young man, yet different at the same time. His short dark hair was now long, lustrous blue. Sharp golden eyes replaced light blue orbs, and a suit of body armor now covers him instead of his uniform.

"Ho… So it seems the weak human had a dormant Sacred Gear! No matter; I will take it and bring it back to Azazel-sama."

What she didn't know, however, was this 'Sacred Gear' user had seen horrors and powers beyond her comprehension. It's even beyond a mere 'Sacred Gear', but something more akin to a deity in and of itself.

His hand formed a blade, Nao smiled lightly, feeling the familiar stream of energy making up the light sword extending out from his hand. Crouching, he focused his energy on his leg before making a leap, launching himself at his adversary at subsonic speed.

The ground cratered at his strength, and a small shockwave was released, blowing the Fallen leaves away. Raynare saw the attack coming, yet she didn't dodge it – because why should she? He's still just a weak and puny human, while she's a powerful Fallen Angel compared to him.

The smug expression quickly turned into horror as the attack tore through her right wing, leaving her unable to take flight. Raynare fell to the ground, landing harshly. She shrieked in pain as her bleeding wing crashed against the hard floor. "But how?! How did this pathetic human get the best out of me? Damnit, I'm an Angel! Father created us! We are always more superior than any of you!"

Tired and annoyed, the Nahobino cut her rant off by kicking her in the guts, returning the 'favor' she gave him earlier.

"'Father'? Whomever do you mean? He's dead, right? Lucifer killed him on the Empyrean," Nao coldly asked, though he was still quite desperate for information.

"I don't know what you're talking about!"

"ANSWER ME!" The Nahobino spat.

"I don't know what you're talking about!"

Seeing he'd get no answer from this one, too clouded by pain and agony, he did the one thing he does best: killing Demons. Taking a few steps back, he gathered his power. Nao raised his blade up. "MURAKUMO!" He shouted, slicing her in half with his energy sword.

The whole town of Kuoh felt that. It was like a small nuclear bomb had exploded. The sheer energy alone might have alerted some Stray Demons, sending them away from here. More work for him then, he supposed.

With that, Fallen Angel Raynare was no more – foolishly killed because of her arrogance, and no one would grieve for her.

Heaving a large breath, he reverted to his human form, though he could still feel Aogami's presence inside of him.

"Stop right there!"

The unfamiliar voice came from a red-haired girl: Rias Gremory.

The to one of the 72 Pillars of the Underworld, and the younger sister of the current Maou Lucifer. But he didn't know her as 'Rias Gremory' – he had never even met her before now. Besides her, there was the long-haired Japanese beauty Himejima Akeno, and the petite white-haired Nekomata, Toujou Koneko.

"My name is Rias Gremory, and I express my gratitude for your help dealing with the Fallen Angel," she said, giving him a courteous bow.

'Gremory…' A name which wasn't all that familiar to him. Nao was sure he hadn't met any 'Gremory' on his tenure at Da'at, but he did remember Bael telling him about a 'Gremory' once before. "Fallen Angel? What's that? And what's the deal with 'Sacred Gear'?" He asked, desperate for information of this strange new world he found himself in.

He didn't know anything about this word. What he had known was only the tidbit of information Raynare had given him during their fight… Well, not a 'fight'; more like a one-sided massacre, but still…

"A Fallen was an Angel who had Fallen from the grace of God due to the sin they had committed. Raynare was a Grigori. Most of them had Fallen due to their lust for humans," Rias answered truthfully as she had felt the shockwave earlier. She knew despite how powerful her Power of Destruction might be, at the moment, it's nowhere near matching the strength of the young man standing in front of her now. The young man did something beyond what Ultimate-class Demons could do, and she had to have him.

"What about you three, then? I can clearly sense you're not human." Nao asked, having not expected to receive an honest reply like that. He wanted to know more, and it seemed the other party was willing to answer his questions… for now.

"We could talk, but not here. I need to take Hyoudou-kun somewhere safe." Rias said, gesturing to the unconscious Issei lying on the ground.

"Why would you want to take him safe? Who are you people?" Nao then asked, confusion in his mind apparent – he didn't know them at all, yet they barged in like they own the place or something.

"We can talk later at Kuoh Academy; it's not that far from here," she said while walking closer towards Issei – trying to get him up and carry him.

"No, it's fine – Diarahan," he cast calmly. The injured Hyodou Issei was now healed, with barely any wound left – it was like he never even got injured; that's how potent it was!

"How did you do that?" Rias asked, gasping in surprise. The two beside her also held similar expressions. In all of their life, they had never seen something like it, only hearing of rare Sacred Gears which could approximate this effect occurring in front of them. ''Diarahan,' he said? I have never seen anything like it before…' she thought to herself.

"A simple spell I learned," he said. He didn't want to answer them since they barely knew each other, and he still held some suspicions about the redhead.

"Then… tomorrow evening, at Kuoh Academy? Meet us there, and maybe we can talk. And I will be taking the boy with me too," she ordered.

Nao shook his head, declined her order, and said, "No, I will be taking care of him myself; no need to worry."

Turning around, he made a motion as the unconscious teen floated up into his arms. Nao began walking away, noting at the bristled expression of the Gremory after he denied her requests again. Using his Nahobino strength in small bursts, Nao made his way across the town in barely a minute, avoiding the general populace's eyes all the while. Opening the door to his supposed house, he got in, dropping the Hyoudou on the couch he saw.

He mused the whole fiasco with the Fallen Angel wasn't going to end well. 'At least it's livable,' he thought, looking around the barely-furnished apartment.

Walking to the bathroom, he saw there was a small bathtub and mirror. Taking a good look in the mirror, he saw Aogami. Shocked, he quickly turned around, and he wasn't there.

'Nahobino, two have become one. Your hearts are now one, and the same,' a voice in his head said – it was Melchizedek talking.

'What did he mean by that…?' he thought. So many questions, yet so little answer. He didn't understand all of this!

'You are one. You are He, and He is You.'

"So you've confirmed it? That the boy has the power necessary to get my silence back?" The voice was emotionless; one wouldn't think it could come out from a girl as young-looking as her. Yet, appearances are often deceiving. One wouldn't believe the young girl here is actually one of the strongest beings in existence – right alongside the Great Red, the Apocalypse Dragon recorded in the Book of Revelation in the Bible.

The girl's identity was none other than Ophis, the Infinite Dragon God.

"Yes, and I've also found an interesting finding, too. It turns out there's a woman spotted near Yokohama, also found during the same time, named Nuwa. Her powers are to be taken seriously, especially with recordings of her defeating our agents from the Old Satan Faction." The man's voice continued his report.

"Defeating Great Red?" The piece of info had piqued her interest; if she were to take his word, then that means she could kick the annoying lizard out of her house better.

"Well, please send some of the Khaos Brigade to hunt Nuwa down. As for the boy, I'd like permission to deal with him myself. There are some discrepancies in the reports we received. He knows of the God of the Bible's death, yet appears to possess no knowledge regarding what Fallen Angels are. The boy is also said to appear human. Through further digging of his profile is needed since we don't really have anything on him at the moment," the man said, before taking out a few pictures from the file he carried, laying them on the table one by one.

"What's this boy's name?" The young girl asked, her voice showing a rare shade of excitement.

"Kiyoyama Nao."

'Kiyoyama Nao… I'll remember that name," Ophis thought silently, unaware of the faintest smile she was making at that moment. And at that moment, their fate was forever intertwined when a Dragon God took notice of a dimensional traveler.