In front of a futuristic looking metal gate stands a bewitchingly attractive young man appearing to be in his early twenties, with light blue eyes and green hair that is slicked back. This man is Ajuka Beelzebub, formerly known as Ajuka Astaroth, Super Devil, genius inventor, creator of the Evil Pieces system and the Rating Games, and one of the Four Great Satans.

As he is standing, he is holding his chin with his right hand in a thinking position, waiting for his servant to finish his report.

"And so," explains one of his trusted servants, an older-looking man who used to be a famous scientist in the human world, his [Pawn] and the head scientist of the current project "Our tests have shown that we have succeeded in creating a gate that can be used to travel to a different dimension."

"Very good work." replies Ajuka, sounding very pleased "Please keep this knowledge a secret for the time being, even from the other Satans. As for now, try to test whether the gate actually works by first using living being such as rats or mice and then report it back to me. While we may have found a way to open a way to different dimensions, we still need to find a way to travel back to our own dimension without building a gate on the other side."

"Will do." replies the man, and leaves.

It has been around eight months since they have found a way to open a gate to another world, and it is currently the year 1905 in the human world. So far they have done tests and have successfully visited quite few different dimensions, some of which where quite strange and some rather mundane.

"My Lord, we have found an interesting universe." says one of the Pure-Blooded female scientists who is participating in this project. "We have found a world in which humans can use magic similarly to us devils. In that world they have something inside their body called Ethernano that lets them use magic."

"Interesting." replies Ajuka "I wish for you to thoroughly research this world as it may hold the answers to our questions."

"Will do." replies the woman, and leaves.

'Soon we may be able to find a way on how to create Pure-Blooded Devils.' thinks Ajuka, while holding a King chess piece.

It has been another two months since they discovered the dimension where the planet is known as Earthland, and currently Ajuka Beelzebub is in the Western Continent, Alakitasia. Ajuka is cursing over another failure, bringing the total now to 12. He has personally been in this world for almost two weeks and the humans who he has tried to willingly reincarnate using the king piece died, and those who were already dead remained dead, thus wasting a total of 12 King Evil Pieces.

As he was about to give up, seeing that none of his attempts were working, and that time moves four times faster in this dimension than in their own dimension, he senses one of his servants arrive.

"Report." orders Ajuka, while not turning around to look at his servant.

"We have found a nearby town 23 kilometers from here which is currently being attacked by a fire dragon, we estimate there will be no survivors."

'Might as well take a look before leaving and use up the last king piece I brought along.' thought Ajuka.

They arrived in the city after the dragon has left, as they did not wish to influence the events of this world with their actions, and saw the city destroyed with many buildings currently being on fire.

"Look for possible test subjects." orders Ajuka, as the continuation of their species being currently more important than any morals "Try to find someone who is young this time, and who might have had decent magical reserves while still alive."

After around 30 seconds, they report that they have found someone matching his requirements.

As Ajuka stands over the dead body of a pink haired young boy who has recently died a few minutes ago, he takes out the king piece from his pocket and puts the piece inside the boy's body, while channeling his own demonic energy inside the Evil Piece, not expecting much at all.

As the Evil Piece enters the boys body and the usual magical energy spike occurs, the boy regains his breathing and Ajuka shows a smile on his face. 'Finally.'

"Take the boy to our dimension and search the house for any information on the boy such as his name, background or date of birth."

After a few minutes searching, the only information they were able to find was that the name of the family was Dragneel and that the boy was their only son. So they left the dimension using the gate.

As the boy with pink hair opens his black eyes, he finds himself inside what appears to be an hospital room, only more modern than what he has previously seen.

"Where am I?" asks the boy, while thinking 'I should be dead. Did someone manage to save me on time.'

Soon two nurses enters the room and see that the boy is awake after having been in a coma for almost a month due to his body adjusting to the Evil Piece. One of the nurses then tells the other to quickly inform Ajuka Beelzebub that the boy is awake, while the other decides to talk with the boy.

"What is your name kid." asks the woman who looks in her early 30's, having brown hair which is in a bun and red eyes.

"Natsu Dragneel." replies the the boy, while also asking "Where am I."

"You are in one of the top hospitals in the Underworld located in the Beelzebub territory." replies the woman, expecting the boy who looks around 7 years to know about it, not knowing the boy did not have any previous interaction with the supernatural world, or that he came from a different dimension.

"Where?" asks Natsu.

"The Underworld is where devils live." replies the woman "Humans usually confuse this place with hell most of the time, due to hell being a part of the Underworld, not knowing that the part where devils live is not a place of punishment."

"I am in Hell!" shouts Natsu and starts to freak out.

Then Ajuka Beelzebub then arrives, having heard him shout out the hell part.

"Calm down, boy, you are not really in hell." assures Ajuka.

Natsu then calms down and says "My name is not boy, it's Natsu, Natsu Dragneel."

"Very well, Natsu." replies Ajuka, and then turns to the nurse and orders "Can you leave the two of us alone."

"Very well, Lord Beelzebub." replies the nurse while bowing to him, and quickly leaves the room.

"Now." says Ajuka "You might be wondering where you currently are, am I right?"

Natsu nods.

"You are not currently in your original dimension but in a different dimension, meaning you are no longer on Earthland. The reason for that is that I have reincarnated you using the king piece due to you being dead, meaning you are no longer human but a devil." after seeing shock on his face, he continues "The reason as to why I reincarnated you is that Pure-Blooded Devils have a very low birth rate in which it takes us centuries to have children. Due to that I wish to find a way to artificially create Pure-Blooded Devils. While many of my other attempts have failed, you were the first success. As for your parents, I am sorry to tell you that they are dead, either in the afterlife of some kind or already reincarnated."

"What happens to me now?" asks Natsu, despite not understanding everything, he now knows that his parents are dead and he is now left alone.

"You will be adopted by me, as you have the king piece inside you, as the Great King Faction may not allow you to participate in rating games due to having it, meaning you can not rise in rank using that way. Due to being a Pure-Blooded Devil despite being a human previously, you will undergo tests by me and my servants in order for me to collect data from you to improve the current Evil Pieces system so that in the future we can create Pure-Blooded Devils ourselves, don't worry we will not hurt you."

"As you are now a Pure-Blood, after being adopted by me you will be made a High-Class Devil, meaning you can start your own peerage once you have come of age, but I will explain that to you later. After we have succeeded in collecting all the data we need and you have mastered you powers, you can return to your own dimension where Earthland is, if you wish, or you can stay here."

"So, what do you say?" asks Ajuka "Would you wish for me to adopt you as my son?"

"Natsu then thinks for a few seconds before replying "Alright," while forcing out "Dad."

Authors notes:

I will make it so that Devils grow like humans until they complete puberty, which for males is around 16–17 years, after that they will age 100 times slower than humans. Natsu will return to Earthland after spending around 100 years in the DxD world while around 400 years pass on Earthland and then join Fairy Tail in x784. He will be raised as nobility due to being Ajuka's adopted son, however he will not have much interaction with other High-Class Devils except maybe Latia Astaroth due to her being Ajuka's niece. He will have a different magic and maybe a slightly different personality. Zeref is not related to Natsu in this fanfiction at all. Natsu could only be reincarnated due to him having an affinity to demonic magic. The gate can only be opened using Ajuka's energy signature or one of his peerage members and only Ajuka's peerage own the blueprints to build the gate. The story will likely be a harem with Natsu having multiple women from DxD and Fairy Tail.