AN: This is a response to a challenge from Iskandar Mandoraekon (Harry Potter and The heroes of Old) initially this will be compliant but after the first summoning (and yes I'm making harry collect 'em all) the set of servants from the anime's will be largely ignored Also I don't own the Harry Potter or Fate franchises, paying me for this is just gonna get us all in trouble.

Challenge requirements:

1) No magic gender-bending.

2) A servant from Grail wars four or five to start off. We'll be going with War five's Lancer, Cu Chulainn.

3) Neglectful to abusive dursleys. I love how many fics write them as nice people but this one won't.

4) The summon will teach Harry their form of magic that the ministry can't detect and therefore won't punish. Done

5) Harry gets an animagus form. I'm thinking platypus

6) Parental Servant. Yup.

7) the Horcrux being dealt with without Harry dying.

8) The servant summoned pre-hogwarts

Challenge DO NOTS:

Yaoi, Supreme overlord Harry, descent from hogwarts founders, demigod status, excessive bashing, nice Dursleys.

Challenge Extras (allowed but not necessary)

1) A different magic school. I am honestly not feeling it sorry.

2) Harry having a reality marble. Yes that's brilliant!

3) New generation marauders with a strict anti-bullying policy. That has potential.

4) Harry being of Creature descent. Yes, but that will be revealed later on.

5) Summoning multiple servants. Love it! He'll get the whole set.

6) Professor Servant. I've always felt Hogwarts was lacking in physical education.

7) A prank war between Harry and Zelretch. No but Zel will be causing a bit of chaos.

8) Harem for a male harry. Yep. I'm scum. Composition to be declared.

Cleaned up a bit as of 1/5/19

Harry Potter was an abused child, that much is irrefutable but on account of some magic a manipulative old man had cast no one seemed willing or able to help him. In truth he desperately wished for a hero to save him, but according to the Dursleys, his Family, "Freaks don't deserve help." In Magus terms the abuse he had endured was causing him to become Distorted.

However being twisted has its own advantages. The Dursley's couldn't possibly predict that their attempts to "beat the freakishness out of him" would only make him more and more "abnormal", that each time they lashed at him him power would only grow as it slowly to prepared to defend him.

Watching on in amusement at this fools errand perpetrated by a walrus and a horse, the multiverse's greatest prankster decided that he'd wreak a little havoc. Zelretch Kischur Schweinorg was an avid student of the butterfly effect. One little change or disturbance causing massive shifts in the paradigm.

A bit of morally questionable magical alteration on the boy while he slept would provide the tools necessary to tip the scales in favor of Harry James Potter. After all the boy had three Dark lords in ten pieces to deal with, and hopeless battles are no fun.

Determining what help could best be applied without his direct intervention would be paramount. Zelretch analyzed him to find four interesting things. One His element was Tactics. Two he had double Origins, Mulligan and Evolution (*1). Three in addition to seventy EX Magic Circuits, he had a magic core. Four the kid had the beginnings of a Reality Marble.

And so Zelretch set to work on the latest of his little distractions. The awakening of the boy's magic circuits was a no-brainer and little more than a wave of the hand for the Saint of the Kaleidoscope. The boy's style of Magecraft, dictated by his element would require powerful familiars made easier to select and acquire by his Origin.

Dusting off old research notes and returning the next night Zelretch removed Harry and one other person to his workshop, carefully making sure that neither of them woke wielding his various mysteries. Within Harry he implanted the summoning system used in the Holy Grail Wars of Fuyuki. Within the other he implanted a magical core taken from a Heroic Servant. Activating the circuits of Subject two revealed that they had thirty circuits, and further research would show that all circuits in their home dimension were Blue Blood type. With the dual elements of Light and Wind, and an origin of Vanquish, this person would if Harry could gain their loyalty be quite useful in the battles ahead.

Just to be on the safe side when Zelretch returned them, he left a manual on the summoning ritual under Harry's pillow. The other would need to figure out magecraft on their own, at least until a Caster was available to train them.

Harry Potter found the book the vampire had left with a cheery note "Hey kid. I've noticed how much crap you put up with from your relatives. I can't intervene too directly but this book should help you get someone who can. Don't bother showing this book to anyone else though it'll only work for you." No signature.

Not that Harry had anyway of knowing this but the book was personally typed by Zelretch, and printed that very night specifically to help him wield his origin to summon Heroic Servants and use his element to employ them in battle. Harry didn't understand why he'd need them to fight but the power to summon a hero was too tempting to ignore. Harry carefully amassed what he'd need for the ritual. That took a whole year.

The ritual circle was drawn with scavenged chalk but it would serve its purpose. To Harry the worst case scenario was that he'd lose a bit of time and maybe wake up late to take another beating tomorrow. Harry thought (correctly) that situation wouldn't get worse if the ritual failed. But if it worked he'd gain a weapon to protect himself from the cruel world around him, and someone he could trust no matter what.

Worth the risk to an eight year old who's been treated like a slave and a punching bag. Screwing his courage to the sticking place Harry James Potter stretched his hand forward to the border of the circle and began the chant that would break through fate. As with most magecraft this aria had been customized for the situation and the caster.

"Fill and shatter five times. By blood of steel and silver. By roots of stone and a promise. Let Arland Evans be the Ancestor. Break the wall between strength and weakness. Seal the power of the foolish. By the four Grand Thresholds, emerge from the Throne and follow the winding road to the battlefield. I offer this contract, my power shall remake your body and your power shall remake my destiny. Let neither of us fear Evil nor Good! If my words resonate with your heart then step forward from the binding circle O Guardian of the Scales!"

It worked. A tall man with blue hair in a wolf-tail and red eyes appeared in the circle. His outfit consisted of a blue tunic with black and grey trousers(*2). He looked around as if he was expecting someone other than a seven year old boy to be present "Oh dear I've been summoned by a five year old boy and there isn't even a Grail War"

Harry corrected him "I'm seven actually. My name's Harry Potter." The Heroic Servant he had just called forth froze like he'd just been hit by a truck and his crimson eyes rapidly widened. "What do you mean Grail War anyway? The book just said I should do the ritual if I wanted a hero to help me."

The man recovered his composure and said "It is irrelevant, I am Heroic Spirit Cu Chulainn, though in public I believe referring to me as Mister Seth(*3) Lancer would be wise." Lancer looked over Harry "That's some impressive magical power you have there, but it's being restrained by something … Oh my."

"What's wrong?" the boy asked.

"Someone implanted a fragment of his soul in your body, It's what's keeping so much your power restrained but I can't identify precisely how or why it was put there." Lancer said confused, "By the Root! I didn't even realize that doing that to a soul was possible. Unless ... oh dear, I've been dragged across dimensions. I guess that explains your unusual powers, of course the rules would be different in another plane of existence."

"Can you remove the soul fragment, or at the very least find out who put it there?" Harry asked. He understood that power was important, but he also knew that knowledge was a form of power as well. Even knowing who put the fragment there and why would be a huge help.

"Of course young master just one moment." Lancer sort of reached into Harry's scar and yanked out something that looked like a ball of green light "This is going to taste awful..." He groaned before eating said ball of green light.

Harry looked on in wonder as Lancer recovered from that bit of unpleasantness "That felt pretty weird for me as well. So were you only able to destroy the fragment, or have you learned anything?" He inquired of his new familiar.

Lancer grimaced as though he had eaten something which tasted unpleasant which was actually in the strictest sense, the truth "The the soul fragment was implanted by a man calling himself Voldemort. I wasn't able to pick up much but he put it there when he tried to kill you, right after killing your parents."

"Huh. Uncle Vernon said that they died in a car crash. Guess that was codswallop." Harry was not at all surprised that Vernon had lied to him. After all the human walrus had demonstrated an immense capacity to lie to himself. Harry checked the back of his hand and noticed his command seals "These marks mean I can give you orders right?" Lancer nodded a confirmation, and Harry used one of them "You are hereby ordered to act as though you were my father!"

This was a highly unusual way of using a command seal. Of course Zelretch had modified how they would work in his case so that over the period of twenty-five days, the seal would regenerate. Furthermore each servant he summoned would have a set of three Seals linked to them and taking shape according to the class they were bound to. For example on Harry's left hand a glaive, a pike and a bardiche would forever more bind him to his first servant, the hound of Ulster.

The Servant's anger continuously mounted as he learned more of Harry's rather unpleasant life. The boy had been systematically beaten and malnourished, and he thought it was legally acceptable. Considering the state of the kid's outfit the Dursleys had almost certainly been misusing his Guardian's Allowance. (knowledge from the summoning system was how he knew about that)

Harry didn't want them harmed too badly so Lancer restrained himself. Infiltrating Harry's primary school as a teacher was surprisingly easy as the previous history teacher had vanished after promising to help Harry. Either he was a total flake or something significantly more sinister was at work.

Lancer investigated this. Somewhat annoyingly every time someone tried to take a look at the Dursleys it had always come up "Vernon Dursley claims that Harry Potter is a delinquent, no evidence exists to suggest this, nor is there any evidence of mistreatment." Yup definitely something sinister at work. It took a month but the Servant identified the cause of this refusal to acknowledge the fact that Harry was abused.

There was a bounded field around Number Four Privet Drive. Immensely complex and quite cleverly geared towards making sure that no one took him out of there. Any mundane who looked at the place would think all was well and believe whatever lies the Dursley's told about the boy. Any magical, aside from Harry and a few others, who looked at the place would not even notice it was there. Whoever placed that ward there was clearly a master of the arcane, and even if he'd kill them after, warranted some serious magical theory discussion.

Horrendous results aside, the ward was a work of art, apparently based off the willing sacrifice of a human life, someone who cared deeply for Harry. Lancer couldn't possibly believe that person would tolerate Harry being treated like some sort of slave!

Seth Lancer rapidly made a name for himself as a good natured teacher who despite, his unorthodox hairstyle was quite effective at making history fun without losing the respect of the students. His housing was solved by renting a room with Arabella Figg, the Cat Lady on Privet Drive. Keeping someone young around is quite advantageous for an old timer.

Cheap housing and few other concerns allowed him to save up money for Harry's future. It also allowed him to quietly supplement Harry's diet. Protein bars, nutrient shakes, that sort of thing. Eventually Arabella asked him about his interest in the boy. Lancer explained what he knew about the abuse. Then he said that he wanted to be dependable, and that Harry Potter looked like he needed someone to depend on.

Harry frequently said he'd been assigned detention with Mister Lancer, much to the confusion of the other students, this was a smoke screen to mask the fact that he had been training the kid in combat and magecraft. This under the table arrangement did raise some eyebrows but the annoying thing about rocking a boat is that first someone would need to care about it, then they would have to dare to do something.

In time Lancer had found a way to shut the Dursley's up about Harry's supposed delinquency once and for all. Ironically magic had nothing to do with it, just a camcorder and some well timed footage. The Dursley's would have enough rope to hang themselves.

It was the April before Harry turned eleven that this occurred at last. Vernon had given him a beat down for once again outshining Dudley in their grades and now it was apparently Dudley's turn. And he brought the whole gang to make the "lesson stick".

"Do you have the camera, Lancer?" Harry asked over their Telepathic link. One of the more convenient parts of the bond.

"This time I'll force these animals to face the consequences of their actions without fail!" Lancer said surprising himself with how protective of his young Master he was being, perhaps it was the Command seal fueled order making him feel that way. Standing just out of sight in his exceptionally ordinary looking business suit. He laid in wait for the fool who was far too please with his own folly.

As predicted Dudley Dursley tried to hit Harry, and the results of Lancer's training the boy showed clearly as each strike was dodged despite the sheer number of his attackers. Eventually though the (admittedly now mitigated) malnourishment caught up him and he began to receive the worst beating of his life. Lancer took his cue, and emerged from the shadows as though he belonged to the Assassin Class.

"Mister Dursley I'll be seeing you in my office tonight, for a mandatory parent teacher conference. I'll see you expelled if you or your parents are not in attendance. Mister Potter I'd advise you to remain on campus until afterwards as I'd imagine things will get somewhat unpleasant due to your present living arrangements." He turned to the rest of Dudley's play gang "The rest of you will have detention tomorrow afternoon. You seem to think it's okay to hit him so I'll be letting him hit you." Lancer dropped casually.

Dudley attempted to brush it off when he brought his parents to deal with the punishment given by the stern teacher who seemed to be out to get him. When they sat down in his office they were offended by the lack of offered refreshments. This was calculated as Harry was munching on a power-bar with a large glass of milk at the time.

"I'm certain that my Dudley didn't do anything wrong." Vernon said slickly "It's our nephew you need to watch out for. I've tried reigning him as much as I can but I'm afraid the boy is a hopeless case." To Vernon's alarm Lancer started to chuckle.

"You and I both know that was load of tosh, Vernon." Lancer was in full teacher mode now. "In the year or so I have known him Harry James Potter has been an exemplary student and a decent if socially awkward human being. Besides in this case it isn't purely Dudley's word against Harry's."

Lancer out the camcorder and showing the Dursley's the incident "Little freak doing his freaky things again! You'll be punished for this. Cheating on your school work, detention too often to do your chores and now dodging all over the place like some pansy freak! You've crossed the line!" Vernon roared.

Harry just took a swig from his glass of milk and Lancer laughed. "Actually just about anyone could learn the techniques Harry used, if they applied themselves. Nothing more than some physical exercises. Pretty much the same can be said for how he's left your son in the dust academically. Harry does the work, Dudley doesn't."

Vernon was slowly turning purple at Lancer's attack on his excuses. "As for the detentions, well that's just what I told him to say. He hasn't gotten a detention in his life because he's a good kid. The reason he's been saying he has detentions is so I can train him without you trying to trample him down like the scum you are." Lancer explained

"HE'S CAST A SPELL ON YOU!" Vernon roared. The portly man regretted saying this immediately afterwards as Lancer was now laughing like he had never laughed before. When the Heroic Spirit finally recovered he sported a bloodthirsty grin.

"So you admit to knowing about magic?" Vernon tried to verbally backspace but it was too late. "That makes this considerably easier." Lancer dropped all pretense, summoned his weapon, it's blood red shaft and blade shining, and equipped his armor. "I am a hero called from ancient legends by the unique properties of Harry Potter's magic and an unwavering cry for help! I'm super-humanly fast and strong on a bad day, and I'm not exactly a klutz either!"

Vernon was shocked into silence "There is nothing you can do to protect yourself from me. There is nothing you can do to keep me from learning about the continuation of this misbehaviour either. Since my existence is fueled by Harry's magical power no amount of wards on your home will ever be able to keep me out as long as you try to keep him in. So whatever idiot left him with you can't protect you either."

That was the end of the status quo.

Lancer's declarations had left the Dursleys numb. In the months afterward Each of them had their own question burning within their soul. Vernon was beginning to wonder if antagonizing the boy had been smart. Petunia was wondering how powerful a wizard her nephew must be to reach across time for help and had correctly concluded that her attempts to beat him down had only made him rise ever higher.

As for young Dudley? He was, much to his own shock, questioning his parents' claims to normalcy. For once in his life he was looking at a distorted situation in a way that made him ask why it got like that. It was the first step down a path that many of his alternates wouldn't begin to consider until later in life.

Dudley's grades shot up and his weight began to go down. While Vernon was rather annoyed that his son was slimming down as he took great pride in his own massive frame, an uneasy peace had been attained at Number Four Privet Drive, a peace which would be shattered when a vampire's other gift reared its head. On July twenty-fourth of that year in addition to what was already expected by Petunia another letter arrived addressed to "Mister D. Dursley of the medium sized bedroom, Number Four Privet Drive, Little Whinging, Surrey"

Well that can't possibly end well...

And that is chapter one of this other crossover. To preemptively answer a few questions, yes I've read the Lupine Horror take on a HP-Nasuverse cross, as well as Neolyph's and a few others. Yes Dudley will also learn Nasuverse magecraft. In point of fact he'll be considerably more of a combat mage than Harry is.

As for the other servants Harry will summon no there isn't a poll and I alone will choose the remaining ones. for those curious however there will be clues leading up to each summoning as between Harry's later studies and the careful acquisition of catalysts will allow rather precise selection in-universe. On a meta level it will primarily be from the Fate Grand Order list

Just to keep track each Bottom AN will have one of these between the main Message and any number annotations.

Servants;

Saber- Not Summoned

Archer- Not Summoned

Lancer- Summoned, cover identity of Seth Lancer established, True Name Cuchulain.

Rider- Not Summoned

Caster- Not Summoned

Assassin- Not Summoned

Berserker- Not Summoned

Numbered annotations:

1. The Evolution part is to excuse the changes they go through from their canon states, the Mulligan (like a do-over) covers how summoning them is more easily accomplished and why most of them have wishes that just having a body again will give them the power to attain.

2. The "Prototype outfit" or my best description of it anyways. For my sanity assume his normal outfit is first ascension minus the metal but in a fight he's in his fourth ascension full armor. If it's different I'll say so.

3. Short for "Setanta" the name given to him before events led to him being called Cuchulain.