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xXx The Infernal Matrimony of Harry Potter xXx
xXx Ch. 01: The Crimson-Haired Ruin 'Puff xXx


xXx A New Story Begins xXx

With wide tear filled eyes, Rias Gremory fled from the room where her father had just informed her that she would be marrying Riser Phenex as soon as she had finished her schooling in the world of humans. The fact that she had been allowed to finish her schooling among the humans was apparently a concession that the Heads of the two houses had made to Rias' mother, Venelana Gremory, née Bael.

Unfortunately not one of the males involved in this farce of a marriage realized that Rias would sooner die than marry that pretentious prick that called himself a High Class Devil. Rias had to wonder what ever happened to her father's sense of affection towards those he considered family that he could so blindly ignore the fact that Riser Phenex was nothing but a bigoted lech that would never consider Rias to be anything more than another notch on his list of conquests. She'd be lucky if she were allowed to keep Akeno and Koneko as members of her Peerage after marrying the arsewipe.

It unfortunately wouldn't be until a month after she had been informed about her eventual wedding that Rias came to a decision that would alter the course of not just her life, but that of an entire society that the people of the three Biblical Factions had largely ignored for over 300 years.


"So let me get this right, if I sign this large sheet of parchment with all of this monumentally complex legalese written on it, it will invalidate the contract between myself and Riser Phenex?" Rias inquired of the diminutive creature sitting in the seat opposite her. Rias had, on a whim, decided to visit one of the banks in the Underworld just to see if one of their account managers might know something which could get her out of the marriage agreement she was forced into. The creature opposite her was a member of a completely neutral species that was the only species all supernatural factions trusted to watch over their finances without stabbing them in the back, the Goblins. "What's the catch?"

The goblin smirked at her, "You are a smart one. Tell me, what do you know of House Peverell, young Gremory?"

Rias frowned at the Goblin, "Not very much. What I do know is that they went extinct around the time that the Great War ended, but before the Underworld's Civil War."

"They aren't nearly as extinct as you might believe them to be," the Goblin remarked. "They merely went to ground in the world of humans. There now exist two people who are descendants of the three Peverell Brothers who participated in the Great War. Of those two, the younger of the two is solution to your problem."

Rias blinked in surprise, "Wait… this solution… is to cancel one marriage contract by activating an even older dormant one, isn't it?"

"Indeed it is," the Goblin smirked wickedly.

"Can I take the parchment and think it over?" Rias inquired, "Also, where would I find the individual you are proposing I betroth myself to?"

"You may, the document will replicate itself and send copies to all interested parties once signed. It is also one-hundred percent unbreakable by anyone other than either yourself or your groom, thanks to a favor being repaid to a certain farsighted individual who is fond of the young man's paternal family," the Goblin explained to Rias.

"Should I be concerned by that bit of information?" Rias asked with a worried tone of voice.

The Goblin issued a throaty chuckle, "No, it is rather the identity of the young man which should concern you. Harry James Potter, the Boy Who Loves to Defy Death."

What followed after that was for the Goblin to give Rias explicit details on how to locate Harry, followed by instructions on how to apply for a one-year foreign exchange program with Hogwarts. Once that was done, all Rias needed to do was leave explicit instructions with her Queen on how to manage the town of Kuoh during her extended absence, which basically amounted to "Make Sona do EVERYTHING!" And with that she was off to London.


"Wizards are such a drag," Rias complained as she sat herself down in the last compartment on the Hogwarts Express. She still couldn't fathom how the Goblin who had been helping her knew that this would be the compartment in which Harry would be seated, but if he was right then she would be meeting the young man in fairly short order.

"Why do they have to wear such antiquated fashions?" was her next complaint, "In spite of how over the top the Kuoh Academy uniform is about displaying all a girl has to offer, it is still far more practical than the uniforms of Hogwarts in a combat situation."

It wasn't until half an hour later unfortunately, that her compartment door was slid open and some people looked into it. One of them, a gangly looking ginger, bellowed out, "Oi, who're you?"

Rias frowned before saying, "Manners normally require you to introduce yourself before asking for the other person's name, however, my name is Rias Gremory and I am a foreign exchange student at Hogwarts this year."

As she was saying this the three newcomers filed into the compartment and sat down, with the rather bookish girl sitting next to Rias as she stated, "I didn't know Hogwarts had a foreign exchange program."

Rias sighed in minor exasperation, but before she could complain the dark haired young man with absolutely gorgeous and deeply green eyes that were obscured by a pair of glasses interrupted, "Forgive my friends, Miss Gremory. My name is Harry Potter, though I must express my surprise at your lack of facial recognition for me, while the boy to my right is Ronald Weasley and the girl to your left is Hermione Granger."

"Thank you, Harry-san," Rias inclined her head ever so gently.

"Why'd ya call him that?" Ron asked in a confused tone of voice.

"It's a Japanese honorific roughly equivalent to the term 'Mister', Ron," Hermione explained. She then regarded Rias confusedly, "You look like a European, though."

"I am of European descent, true. However my family's primary residence is in Japan," Rias explained to the others, "Oh and you are only partially correct. Most Japanese honorifics are unisex, the one notable exception you would very likely be aware of without needing to look it up, Hermione-san, would be the one a lot of people back home refer to me by, Rias-hime."

Hermione looked confused, "That's a bit pretentious, don't you think?"

"What does it mean?" Ron asked.

"Princess," Harry replied, "The people in her hometown refer to her as a Princess… how do I know that?"

Rias' eyes locked with those of Harry and with a smirk she said, "More accurately they refer to me as Mezatsu Hime." She adored the look of shock she saw in Harry's eyes when he succeeded in translating that phrase.

"Right… um, Ron, Hermione, whatever you do, never piss this girl off," Harry remarked, "Trust me when I say that judging by her nickname back home… it will not end well for either of you."


When she arrived at the Hogwarts Great Hall, Rias was greeted by a rather frumpy looking woman who was apparently the Herbology Professor, and who informed her that she'd be required to sit under the Sorting Hat like every other new student to Hogwarts. So when it was her turn under the hat, she wasn't at all surprised that a problem occurred.

"Right then, most unusual." the hat declared loud enough for the entire hall to hear it.

"Pardon me, Mister Flopsy," the voice of the Headmaster spoke up. "But what is it that is most unusual."

Rias muttered just loud enough for the hat to hear, "Divulge my species and I use my Clan's trademark power on you."

"I am afraid Albus, that I am not at liberty to divulge anything I learn about a particular student in their time beneath my brim, as you well know." The hat replied with an even tone before it spoke into Rias' mind "I see great fear in your mind, but also a great deal of hope. Fear of being forced into a marriage you cannot possibly find love within, and hope that a certain young man can save you from that fate. Tell me, daughter of Gremory what do you have to offer to our young Mister Potter that he cannot find elsewhere?"

Rias frowned, she had not expected that line of inquiry as a means to determine which House she belonged within. What was worse, she knew practically nothing about Harry at this point in time outside of the fact that he was apparently incredibly famous in this society for something that happened to him while he was still in nappies.

Rias had to immediately squash her first thought on what she could offer to him. Adding him to her Peerage as a means of providing him the family he had never known was an incredibly stupid idea on multiple fronts. For one thing, she had by now read that contract she had been given and was aware of the fact that such a move would invalidate it unless she was doing it for the express purpose of saving his life in a situation where he had no other hope of surviving. Secondly, while Harry was a remarkably powerful spellcaster, Rias only had one Bishop left and she was loathe to use it on anything but the most promising of individuals, preferably someone with a Sacred Gear. There were a host of other reasons it was a bad idea, but those were the two most noteworthy.

That was when she began analyzing the events she had read about in the Wizarding Newspaper during her time in London while shopping for school supplies. She had actually ordered several back issues of the Daily Prophet as well as a curious magazine known as the Quibbler in order to research current events. In those issues she found reports dating back three years of increasingly frequent situations where the lives of the students of Hogwarts had been in danger, and in almost every single situation those problems came to a resolution thanks to the actions of three students, only one of which was named, Harry Potter.

Those articles, combined with the terrorist activity at the Quidditch World Cup earlier this summer led to a startling realization for Rias, "That is what I can do for him. I can teach him how to take advantage of his birthright so that he isn't vulnerable to attacks from Voldemort and his sycophants."

"Ah, clever girl." the hat replied before bellowing out the word "HUFFLEPUFF!"


At the Gryffindor Table Ron Weasley barely stopped himself from laughing, "Another useless duffer, that one."

"That's not nice, Ron!" Hermione reprimanded their mutual friend.

Harry however, had been unable to keep his eyes off of the slightly older girl ever since he first saw her. Admittedly she was incredibly beautiful, but that wasn't why he couldn't stop himself from staring at her. Rather, it was the fact that he couldn't shake a feeling of recognition. There was just something about this girl that he couldn't help but find familiar. If he had expressed that sentiment to either of his two friends, well they'd likely say that it was cause she bore a passing resemblance to his mother. Truthfully, Harry did not find her to resemble his mother at all, there were just too many differences to list them all, the least of which was the fact that she still wasn't out of her teenage years and already her breasts were significantly larger than his mothers had been.

"I still can't believe that we sat with a Veela," Hermione continued in utter annoyance. Harry frowned, based solely on his recollection of the Veela at the World Cup, he was absolutely certain Rias wasn't one, but he had long since learned not to argue with Hermione once she has formed a hypothesis, no matter how erroneous he might know that hypothesis to actually be. The same could be said for Ron actually, both his friends were extremely bullheaded.


Hannah Abbott and Susan Bones couldn't help themselves as they stared at their new dorm mate in utter and complete shock. "I didn't think it was possible, Susan…"

"Her… her…"

"Boobs?"

"Boobs… are bigger than mine…" Susan stuttered out.

"Yep!" Hannah agreed with a cocky grin.

Once Rias was seated and it became obvious that the boys at their table were staring at her merely because she was an extremely beautiful female, rather than because of any other reason, Susan ground out, "You're not a Veela, are you?"

Rias eyed the girl curiously for a moment before shaking her head in the negative, "No I'm not."

"Then you must be one of the most beautiful humans to walk the earth," Hannah complimented.

Rias smiled a smile that barely hid how ironic she found those comments to truly be as she replied, "Why, thank you."


After the meal, the Headmaster made an announcement that upset pretty much the entire school, Quidditch, whatever that was, had been canceled for the year. Then he announced that in its place the school would be playing host to an event known as the Triwizard Tournament.

"Well fuck," Rias swore moments after the announcement was delivered, though only loud enough for the girls opposite her to hear her.

"Something the matter, Rias?" Susan asked.

"Nothing's wrong at the moment. Though there will be if I die. My family is extremely powerful politically speaking and will more than likely have our nation declare war if that happens," Rias remarked, though she would refuse to be blamed if they misinterpreted her statement to mean Japan would declare war and therefore believe themselves capable of winning.


Much later that evening inside the Hufflepuff Fourth Year Girls Room a group of young girls found themselves to be ever so slightly shell shocked, "You mean to say…"

"That is correct, I have a very hard time sleeping in any form of clothing, and people who I've invited over for slumber parties in the past have informed me that I 'Sleep Disrobe' much like how some people will 'Sleep Walk'." Rias explained to the other girls as she divested herself of the last of her garments.

"Rias, you are by far the most unusual and might I add, frightening, person I've ever met who is the same age as we are," Hannah remarked, "And that is a considerable achievement given some of our friends."

"Yeah, I agree," Susan joined in, "Not even Lucius Malfoy would be capable of sending England to war if Draco kicked the bucket, despite what they like to believe."

"I assure you, I wasn't lying about that," Rias remarked in an off-handed manner.


Meanwhile, all the way back in Japan, an absolutely furious Student Council President threw open the door to the Occult Research Club Room and roared, "WHERE IS SHE?"

"Where is who, Kaichou?" the voice of Akeno Himejima inquired from where she was sitting in the seat normally reserved for the very person that Sona Sitri was currently demanding the location of.

"You know very well who I am talking about, Himejima-san. Now talk!" Sona demanded.

"I haven't the slightest idea to whom you are referring, Kaichou," Akeno remarked with a cheshire cat grin. What few people would realize unless they actually interacted with her meaningfully, was that Akeno Himejima absolutely loved torturing people, even if not in a literal sense of the word.

"Cut the crap, Akeno! Tell me where Rias is, and tell me now," Sona demanded with an angry glower towards the other girl.

"Ah, well as it happens, she is investigating a matter of some urgency that has forced her to be absent from Kuoh for this entire year. I am therefore the acting club president for the foreseeable future, and have been empowered to handle all that such a station requires, except for the duties of territorial administration," Akeno explained as delicately as she could manage.

"You have got to be kidding me," Sona said dryly. "She's gone on a vacation to who knows…"

**POOF**

"Heya!" the voice of Rias' familiar called out as she appeared within the room, "Am I interrupting anything important?"

"Oh, hello Buka-chan," Akeno said in greeting, "Something happened already? That was fast."

"Rias-sama hit a bit of a road bump that she hadn't foreseen. Does Sona-sama know what is going on yet?"

"Not yet, but one of the two of you will now be informing me, of that I am certain," Sona replied.

Buka eyed Akeno wearily for a moment before turning her attention to Sona and saying, "Rias is currently attending Hogwarts School of Witchcraft and Wizardry."

"And just what is Hogwarts exactly?" Sona asked in slight confusion.

"I'll take that explanation, Buka-chan," Akeno replied, "Sona you are no-doubt aware of the fact that some humans will make contracts with Devils in order to learn the secrets to our magic. The same is doubtlessly true for the various other factions. However what seems to have flown completely under the radar, or perhaps it was merely forgotten, is the fact that some humans don't need those contracts in order to utilize magic. Hogwarts is a school for such humans to learn the finer points of their brand of magic."

Sona frowned as she considered that explanation, "Why have I not heard of these people before?"

"Actually, you very likely have," Buka remarked. "Two of the earliest known students at Hogwarts were Morgan Le Fay and Merlin Emrys, which incidentally means the school is older than most people today believe it to be. That said neither individual was exactly fully human, were they? More to the point, it was that group of humans that is largely responsible for the inquisition period getting as bad as it did."

"What do you mean?" Akeno asked in a curious tone of voice as she eyed Buka.

"Pretty much everything that the Malleus Maleficarum claims as proof of a person being a Witch is something these people learn to do in their first two years at a school like Hogwarts. Which means that they can do these things without a focusing implement for their magic once they get older. While reading the required textbook for the History class at that school, Rias-sama found anecdotes of people making sport out of how many times they were burned at the stake," Buka explained.

"Okay, I'll believe you about the existence of this school and Rias' attendance therein," Sona replied tentatively. "But why is she there, and what is the roadbump?"

"She's investigating the viability of a potential escape clause to the marriage contract between her and the yakitori reject," Koneko spoke up from where she had just entered the room and heard the question. This naturally surprised everyone as that was one of the longest sentences the stoic girl had ever used in any of their presences. Koneko looked at them all for a moment before saying, "Bite me." She then sat down and began eating some of the delectable cakes that were set out for her.

"Well that is certainly a surprise," Akeno said in an amused tone of voice, "But she is correct, Rias is investigating a possible solution to her most pressing problem. As for the road bump…"

"Not so much a road bump as it is a SNAFU," Buka remarked.

"Oh dear, what has Rias gone and gotten herself into this time?" Akeno inquired in an amused tone of voice.

"She is attending Hogwarts during the same year they decided to revive the Triwizard Tournament of all things," Buka explained, "Which is sort of like the Olympics, if the Olympics had a higher chance of spectator casualties than a gladiatorial contest back in ancient Rome."

"I suppose my presence in this room during this conversation wasn't an accident, was it?" Sona drawled, "I hate you three utterly and completely, you realize that, Buka-chan, Akeno-chan?"

"Me too?" Koneko asked in a frosty tone of voice.

"Nope, I still adore the cute and cuddly Koneko-chan," Sona replied as she moved over and hugged the smaller girl. "You and Gasper-kun are pretty much the only tolerable members of Rias' peerage in my opinion. Well, perhaps Kiba-san too."

"Anyways, will you ask your sister to act as an impartial observer for the three major events of this tournament so that Rias-sama can be reasonably certain that there won't be civilian casualties, least of all in the form of her own life?" Buka inquired.

"If I must," Sona replied dryly, "But I do so under protest."

What never got said by any of the people in that room, was their concern over just how a race as long lived as the Devils could have misplaced the knowledge of an entire population of humans that could use magic without requiring the intercession of any of the other species that interacted with humans. What they didn't know, what they couldn't know, was that was the fault of a trio of brothers who made a pact with Death herself.

xXx Chapter Conclusion xXx

Author's Note: So I am going to try and write this in a manner where everything isn't just immediately solved right off the bat, but I make no promises. Rias is attending Hogwarts and Serafall will be watching the tasks, but Serafall will not be interfering with those tasks unless there is a significant risk to Rias' life.

I should also note that at the current point in time, this is not planned as a harem fic, though that could easily change over time and very likely will change. Rias won't like that change if it does happen, as she is noted for not liking the prospect of sharing in the canonical series.

Lastly, Harry is not a replacement for Issei. They both exist and will both be involved in the plot.