Hey everyone! Thunderito here with a brand new story! So, the two most requested stories were the Naruto/Sao and the Naruto/Rosario-Vampire. However, Rosario won by one vote, so that is what I will do. This is an introduction to the world, just like Alpha Bijuu. Now, the story's name is The Demon God. With no further delay, on with the start of a new story!

Chapter 0:

The Monster World. A dimensional world, home to all races of Monsters. Split from the Human World by a Dimensional Barrier, it was created from the Gods. Some say the Gods created the Monsters, to test how lifeforms would adapt with powers. Some say they are freaks of nature. No one truly knows what was the true reason of the existence of the Monsters. What is known, however, is that Humans and Monsters were in a never-ending war, each one wanting to exterminate the other. However, the Dimensional Barrier of the Gods forbade it. So, the majority of the Monsters were secluded in their own world, growing in power and knowledge. They formed organizations and positions of power, usually complemented by the power of a race. They created a Monster Ranking System, with the lowest being E-Rank and the highest S-Rank. In the entire world, only 4 known races have been accepted as the dreadful S-Ranks.

First were the Youko. Youko were humanoid creatures, the size of humans or taller, with intricate tattoo-like markings all over their body. They possessed tails, the more tails a Youko had the stronger it was. The strongest Youko's in history were mostly with 8 Tails. They were rumoured to have the blood of a Kitsune, because of their famed KitsuneBi. The second race was the Phoenix. Phoenixes were large, majestic, fire-covered birds with glowing eyes and tremendous size. They had incredible power, as a fully-charged blast of their fire were strong enough to bring down mountains. They were quite secluded, in the peaks of volcanoes, coming down only for hunts and war, or for special occasions that have to do with the entire Monster World. The strongest were the Black Phoenixes. The third race was the Werewolf. Werewolves are Human-looking beasts, though under the effect of a moon, they transform into large Wolves, walking on two legs, with incredible power and unmatched speed. The strongest a Werewolf can go is under the effect of a full moon. The most powerful Werewolves, called Alpha Werewolves, however, are capable of transforming any time, though their strength does increase under the moon. Finally, they were the Vampires. Vampires are human like monsters of great beauty. They usually have red eyes and fangs to suck out blood. They possess monstrous strength, toughness and huge reserves of Yoki power, the energy of the Monsters. They are considered the strongest monsters, with only werewolves able to match their combat prowess. Among them, the descendants of the Shinso were something like royalty.

However, there once existed a race of ten beings far greater than even the Vampires. So terrifying, so strong, that the Monsters couldn't rank them as even SS-Rank, a title so rare that only a few Shinso Vampires, Alpha Werewolves, 8-Tailed Yoko and Black Phoenixes were capable to reach. They were called, the Bijuu.

It was in the Dark Ages, the time of Alucard, otherwise known as the Oldest Vampire, a few centuries before he was defeated by the Three Great Dark Lords. Ten beasts appeared in the world, so powerful that even Alucard was weak against them. They took over the Monster World by storm, with many great Monsters attempting to defeat them, either for fame and fortune or to be rid of their threat. Only Alucard was capable of barely defeating their lowest in power, however, he suffered great injuries, injuries that didn't heal even during the time he was defeated by the Dark Lords. Their strength was so great, that they were considered the royalty of Monsters, Godlike beings that crashed down to the earth, with their leader widely regarded as a God of Monsters. All of the Bijuu were always in their large Monster Form, to display their fearsome strength, except their leader, who didn't need to.

The first of the Bijuu resembled a Tanuki. It's skin was a sandy brown colour, with dark blue markings running all over his body. He had a jagged mouth with no tongue. It's eyes had black sclera, with yellow irises and pupils resembling a four pointed star, with four dots around it. It possessed one large spiked tail. It was called the Ichibi.

The second Bijuu resembled a Bakaneko. It's body was completely engulfed in azure flames. It had two different coloured pupiless eyes, one green and one yellow. It had two tails behind it, also engulfed in azure flames. It was called the Nibi.

The third Bijuu resembled a Turtle. It had a grey crab like shell, with spikes running all over his body, except the belly. It had red muscle tissue, with a pair of grey hands, but no hind-legs. It's face was covered by a spiked forehead and jaw, with one red eye with yellow pupils. It had three shrimp-like tails behind it. It was called the Sanbi.

The fourth Bijuu resembled an Ape. It had the body-build of a Gorilla, with red fur and green skin. It had yellow irises with white pupils. It's face had elongated blunt fangs and two large horns in his forehead resembling a crown. It had four large tails, with spike-like protrusions running along them. It was called the Yonbi.

The fifth Bijuu resembled a Horse, but with the head of a 's fur was white, with tanned horns and hooves. It;s dark blue-green eyes had red markings below them, It had five white tails and it was called the Gobi.

The sixth Bijuu resembled a large Slug, It was white with a bluish tint. It was bipedal, with small arms and feet. It had optical tentacles for eyes and holes for a mouth. His entire body, from his head to his six tails, was covered in a slimy substance, It was called the Rokubi.

The seventh Bijuu resembled an armoured Kabutomushi, the armour blue. An orange glow came from inside it's helmet-like skull. It had spikes on it's shoulders, with a row of slits below them and six legs, three on each side. It's face had two pincers and two large horns. It had six tail-like orange wings, with an actual green tail. It was called the Nanabi.

The eighth Bijuu resembled an Ushi-Oni, with four large horns on his head. It had a muscular upper body, with spiked protrusions on the elbows. It had straight teeth and pure white eyes. It had eight octopus tails growing behind him, using them as legs. It was called the Hachibi.

The ninth Bijuu was the biggest, resembling a Kitsune. It had red fur, with the upper body resembling that of a Human. It's eyes were red with slits. It had nine enormous tails running behind it. It was called the Kyuubi, Master of the Youko's.

The tenth Bijuu had a different appearance, as it was always in it's human form. It stood at 6'4 with a ripped frame. His hair was golden, with black streaks running through it. He had blood-red eyes, with slit pupils similar to a wolf. His face was angular, with a strong jaw and three dense whisker-like marks on each cheeks. He was wearing a dark grey robe, concealing his entire figure. A black Yoki aura with a red outline surrounded him, with 2 wolf ears and 10 ethereal white tails with red outline behind him. He was called the Juubi, God of Monsters.

The Monsters tried for a long time to bring down the Bijuu, though each attempt failed, as the Ichibi alone could take on an entire battalion of Vampires. A lot of Blood was spilled throughout the years, so they turned to Sealing. Through the loss of many lives, they sealed Eight Bijuu inside different, isolated locations in the Monster World, powered by thousands seals and Holy artifacts. The Kyuubi was sealed in another dimension, as it's power was too great to be contained in any location. The Juubi escaped with little effort, swearing to free his brothers and sisters. For hundreds of years no one has seen him.

The years passed and the tale of the Royal Monsters became a legend, with only the still alive survivors remembering the horrors of that war. But soon, everything would change. The world would soon feel, the power of the Demon God.

Yokai Academy

In the Headmaster's room of Yokai academy, sat Tenmei Mikogami. He was one of the Three Dark Lords, one of the most powerful demons of his age and is known as the Exorcist, as he wore clothes resembling a priest. He was sighing, dealing with paperwork. Suddenly, he felt an enormous wave of pressure fall upon him, so strong that he fell to the floor in pure fear. He knew this aura, this terrifying power, this otherworldly energy. He was only a young demon back then, but he knew it. He looked up, pure terror in his eyes and saw Him. He stood in front of the closed door, looking exactly the same as he did back then, with his clothes the only difference. He had his arms crossed and was looking down at him "It's been a long time Tenmei Mikogami. My name is Shinju Naruto but you can call me the Juubi no Ookami." he said, in a tone of great power.

Woohoo! Hope you liked the introduction to my new story! Tell me what you thought of it. Advice and questions are appreciated, flames ignored. Now, for all those who will ask, this will be a Harem. Moka is in it, both Inner and Outer. I don't know about Kurumu, Mizore or Ruby, but there will be other women too, specifically Akasha and some Demons that aren't in Canon Rosario Vampire. Naruto has Rinne-Sharingan for those who wonder. Any other questions, feel free to send. Thunderito out!