This is my first story that I actually think has the potential of being complete. The first chapter is a mix between a summary of what happened in-between the anime and the story and the prologue.

Disclaimer: I don't own Harry potter or Blue/Ao no Exorcist.

Talking: "I am talking."

Japanese: "I am talking Japanese."

Thinking/mental discussion: 'I am thinking. '

Writing/flashback: I am writing/having a flashback.

Three months after what is known as the 'Gehenna Gate Disaster' Rin started losing parts of his memory. What no one realised was that Rin had been possessed by Satan who was biding his time trying to fulfil the dream that he and Yuri had built (the Demon and Human world meeting). When Satan fully posses Rin, Rin fights against it. To convince Rin to stop fighting him Satan gives him the same memories he gave to Yukio, Rin however calls Satan stupid and tells him that Yuri did not mean meld the worlds literally but for the Humans and Demons to work together and that what Satan was doing would probably ruin any possibility of that dream ever coming true. Satan realises the truth in Rin's words and leaves Rin's body returning to Gehenna. However there were side affects to Satan staying in his body for so long, it formed a kind of telepathic connection between the two were they could hear snippets of each others thought or emotions. After a while they could have conversations mentally, through this Rin formed a shaky alliance between the True Cross organization and Satan; Satan would do his best to stop the more powerfully, dangerous demons from crossing over and the True Cross would not kill any demon that was not a threat to humans. The connection also caused Rin and Satan to develop a kind of father/son relationship. Satan started training Rin to control his powers better (including how to summon his own Gehenna Gate) and also gave Rin a dagger that he confessed held 2/3 of his power that Satan had sealed there at his birth as Rin's body would have burnt up otherwise. Yukio knew of the training even though the True Cross did not. There was one thing not even Yukio knew though, which was the fact that Satan had declared Rin his successor on the off chance that anything happened to him, the only people privy to this knowledge were Satan, Mephisto, Amaimon and Rin himself. Satan also reviled to Rin that Mephisto and Amaimon were his two half brothers (Yukio only knows about Amaimon being related to them) who Rin also grew close to. Just after turning seventeen Rin passed the Exorcist exam, becoming a Knight and a Dragoon using a gun called 'Thanatos' that allows him to uses his Satan's flames as ammunition.

August 2nd 1994 –

To whomever it may concern,

Six years ago my twin sons, Rin and Yukio, and I were contacted by a representative from the Jumonori magic academy. They informed me that my sons had a latent magic ability that was likely to wake in the next seven years and gave me any instructions if this were ever to happen. Their powers started showing two years ago when there was a hostage situation at the boarding school they both attended; their powers however did not wake fully for another year and a half. When I contacted my contact they informed me that the school had been destroyed two years ago and had not been rebuilt, I was told to look over seas as not many other schools in Japan would be willing to except a student past the age of eleven. They also told me that Hogwarts is one of the best and that they treat everyone equally. What I am trying to say is that I would like my sons to attend your school.

I hope you will get back to me with a positive answer soon,

Takashi Okumura

August 8th 1994 –

Mr. Okumura,

I would like to accept Rin and Yuki into Hogwarts but as I am sure you are aware a few things need to be sorted out first. Am I right in assuming that neither have any magical knowledge and experience and that they are both seventeen? That is the last year for us at Hogwarts so they would have to go into a younger year, the fourth year being the best as students sit O. at the end of their fifth year. In your reply will it be possible for you to send birth certificates, medical information and the sorts? It would make this much easier.

With my regards,

Albus Wilfred Percival Brian Dumbledore,

Headmaster of Hogwarts School of Witch Craft and Wizardry

August 14th 1994 –

Mr. Dumbledore,

I am glad that Rin and Yukio are likely to have a place in your school, yesterday Rin set the table on fire by accident, they need to be able to control their powers. They were a bit reluctant but I talked to them and they have agreed that it would be for the best. In the envelope should be all o the information that you might need, I hope it is enough.

Sincerely,

Takashi Okumura

August 20th 1994 –

Mr. Okumura

I am pleased to inform you that Rin and Yukio have been accepted into Hogwarts School of Witch Craft and Wizardry. They will be entering into fourth year and are expected at Platform 9 ¾ on 1st September, Kings Cross Station, London, England. Any additional information can be found in the individual letters sent to your sons. They can buy all of their supplies in Diagon Alley of Charing Cross Road .Will you need transportation to get to London?
With regards,

Albus Wilfred Percival Brian Dumbledore,

Headmaster of Hogwarts School of Witch Craft and Wizardry

August 26th 1994 –

Mr. Dumbledore,

I am glad to hear that Rin and Yukio are welcome in your school. I thank you for the offer of transportation but I already have something organized.

Sincerely,

Takashi Okumura

Just in case people don't realise it Takashi Okumura is Satan's human alias. Sorry for any spelling or grammatical errors, I do have a BETA MissBliss8527 but there might be a few thing that both of us missed. Please review it is much appreciated.