Forgot to do this cause I posted it in a hurry but basically I don't own either Naruto or Hunter x Hunter so don't sue me. I wanted to make a hunter x hunter crossover story that starts similar to a story I saw on the crossover section but takes a different route and that story inspired me to do this. I checked the authors profile and saw that he didn't really mind if someone took a similar idea so I started writing this and just decided to post it.

Naruto twirled the quill that had appeared out of nowhere in his hand. Next to him was a bottle of ink that had also appeared out of thin air and on the floor between him and the youngest child of the Zoldyck family, Alluka, was a parchment. He could feel gazes boring into his back from everyone else that was in the room. Well even if they tried anything funny they couldn't go through with it unless they wanted the old guy to die.

Why would he die you ask?

Because of the contract they had made of course.

Naruto was seven at the time. He was in the 'custody' of a mafia family. It was 'custody' because they had pretty much forced him to work for them but they did reward him whenever he completed a job so it wasn't all that bad. It sure as hell beat living in that hellish orphanage; where there was barely enough food for him and whenever things got boring the caretakers would amuse themselves by using them as punching bags.

The blonde was heading to his room after having completed another job. This time it was to make a contract with some dude that worked for another of the mafia families and whom had tried to spy on them or something. The contract was pretty simple in all honesty:

'Obey our demands or you'll die. In return you will be released after we have what we want.'

Even though it seemed otherwise the contract was incredibly vague, which bothered Naruto to an extent for some reason, but it was powerful nonetheless. Every single word that was written in it was true. The reason it was vague was the second verse of it. Whilst the first was pretty simple and binding the second was open to an extent which meant that it could be interpreted in a number of ways and it would still fulfil the contract.

It was an abusive use of his ability.

The mafia had discovered that whenever Naruto made an agreement, contract or any form of deal where an exchange would be made he could make the rules, requirements or conditions on said contract actually happen, no matter what they were.

'Well whatever, that guy was probably going to die anyways.' Naruto thought without a care. After having lived with the mafia family for a year he had made loads of contracts and most of the time it was always something along those lines so by now he wasn't bothered as much.

Getting to his room he opened the door and went to take a shower. His room had his own personal shower, along with all the other necessities of a room but he also had his own personal fridge. Ten minutes later Naruto was feeling refreshed although he was still a bit tired. Making a contract was a tiring affair so his max was five contracts a day. Today was a really slow day because he had only made one although he usually made four to five every other day. They had discovered that if Naruto tried to make more than five contracts a day it simply wouldn't work and he would be knocked out for a week due to sheer exhaustion.

Sitting on his bed whilst sipping a carton of chocolate milk and in his pyjamas Naruto almost had a heart attack when he heard a voice from the direction of his window.

"That seems like an interesting ability."

Naruto choked on his milk and spurted it out whilst falling out of his bed and snapping his head to the window. Standing by it was an old man of medium height with grey white hair who was garbed in purple clothes.

Naruto stared at him wordless. And the infamous Zoldyck assassin Zeno only stared back.

"You aren't going to panic. How strange, most people would." The ancient assassin continued without a care in the world. The boy in front of him only continued to stare for a few moments before he got up from the floor and went to his mini fridge. He opened the door and got another two milk cartons from it. Returning to his previous position on the bed he opened one and threw the other at the old man and said, "You've got a weird moustache old dude."

Zeno caught the milk carton in his hand and hummed as he watched the boy sip his chocolate milk whilst observing him. The kid was pretty weird. Not as weird as some of the people he had been hired to kill previously but weird nonetheless. He had definitely not expected that kind of reaction from him. Deciding to try and get another amusing reaction out of him he shared the fact that he was intending to kill him now. It was a lie but the kid didn't know that.

"There's a hit on you kid and I took it. I'm going to kill you now." Zeno commented to the young'un in front of him and watched his target curiously.

"No you're not. What do you actually want?" Naruto replied back in between sips of his drink. Zeno looked at him for a moment before he sat up on the window sill and opened his own carton. He began to take sips from it while preparing his response.

"Is that so? I wouldn't be too sure, I never fail a contract kid." He shot back at the kid. He was definitely one of the strangest kids he had met and considering the fact that he had a hand in training Illumi that spoke volumes. Who in the world would talk down their would be assassin whilst sipping chocolate milk?

"Cause I can feel you don't want to. Plus I didn't even notice you until you spoke which means that you could've been here since the moment I walked in. If you wanted to kill me you would've done it by now right?" The small blonde calmly explained his logic to the elder that quite frankly held his live in his hands at the moment. All that Naruto had said did make sense but it excluded a couple of facts. His ability to sense bad intentions in people towards him wasn't omnipotent and definitely didn't keep him away from danger all the time. Besides just because he could not feel any intent to harm him from the old dude at this point in time did not mean that he didn't want to kill him; it simply meant that either this guy was so skilled that he was hiding his emotions entirely or that he simply did not have harmful intentions because he hadn't made his mind up whether he was going to kill him or not.

However what made Naruto kind of confident in the fact that he was not going to die today was the fact that the old man in front of him started laughing. For a second Naruto relaxed before his eyes widened and he immediately tried to shush the old timer.

"Shush! Everyone is gonna hear you dumbass!" Naruto whisper shouted at him and made a shushing noise. Zeno calmed down and looked at him with amusement. "It doesn't matter really. Say kid I've got a job for you, you up for it?" The old man casually said with whilst his eyes twinkled in mirth.

Naruto stopped with a puzzled expression. He frowned before replying, "Well I don't really mind as long as it isn't too dangerous… but anyways what do you mean it doesn't matter if they hear you?" Zeno chuckled and threw the milk carton in a bin on the other side of the room. "It means that they wouldn't be able to do a thing even if they found me." Further confused by the strange old man's words Naruto tried to figure out what he meant.

'Is he implying that he's strong enough that even the dozens of armed guards aren't a threat at all? This guy must be one hell of a monster then…' Naruto's thoughts trailed off as he heard footsteps thudding down the hall towards his room. He stared at the old man in front of him as a voice called out from outside his door.

"What're you laughing at kid? Hurry up and go to bed already, you got a full day tomorrow!" The mafia thug reminded him loudly before turning around and storming down the corridor. He was sure that there was something wrong with the mansion tonight. Something felt odd about it even though he couldn't quite put his finger on it…

After making sure that the man had gone Zeno spoke again, "You didn't call out for help. Are you that interested in the job I have?"

Naruto replied to him, "I don't mind going on it but… You have to take me away from this place for good." The blonde made his intentions clear. He was gonna use Zeno to break out of the mafia family's control and supervision? That was fine with Zeno since he had to take the boy with him anyways for what he had in mind.

This entire thing had started when he had gotten a hit on Naruto. At the time he didn't know his target was this weird kid, the only information he had was that his target was a powerful Manipulator that was causing trouble for other mafia families by making their men turn on them. Thus one of the families had decided to get the pros involved and Zeno had answered to the call of the mission. He had no idea that the 'powerful Manipulator' was actually a seven year old who had blinding Nen potential.

The kid was most likely actually a Specialist. And he was also a Nen genius, someone that without instruction was able to use Nen powers that came to him instinctually. Most of the time these Nen geniuses were specialists whose powers awakened and worked without their control or consent but in some cases the user could figure out how it worked and thus figure out how to consciously use his/her ability.

This wasn't, however, the entire reason as to why the kid had amazing potential as he had concluded. It was because, at the moment that he had made the contract with the man downstairs Zeno had felt the amount of Nen that had been released. It was an amazing amount for someone his age and most importantly for someone that had not been trained in Nen at all. What this meant was that Naruto himself had an incredible amount of Nen already and that his ability was so powerful that it used a big amount of aura to activate. This told Zeno that it was most likely a troublesome ability and that it was capable of powerful feats.

It was exactly what he needed.

The moment Zeno had observed the activation of his ability downstairs and felt the amount of power it put off he had made his mind.

He was going to take this kid back with him and make use of his ability to find a solution to Alluka's situation. But first he needed to confirm some things.

"Hmmm I'll agree if you explain how that ability works." Naruto nodded his head before making a request.

"First can you tell me what exactly it is that I'm doing? I mean I know how it works but what makes it work and exactly how am I doing it? I've played around with it a little and found some cool stuff but it's really weird if I'm honest. Most people in the house act as if it's natural but I can tell that even they don't really understand it. The only one who seems to is this other guy and the boss too but I have no idea what's going on to be honest. I've never seen anything like it before." Naruto explained as he crossed his legs on top of his bed and threw his own chocolate milk in the bin.

Zeno sighed and began his explanation.

An hour or so later the old assassin had explained that Naruto was using his Nen to do the feat he accomplished downstairs and that Nen was life force, energy that everyone had but only those who went through special training could make use of it. That had made Naruto immediately question why he was able to do what he could even though he was pretty sure he hadn't been trained in this at all. Zeno expanded upon his explanation that some people in the world could simply use Nen without any instruction. It was a very rare occurrence but it did happen sometimes. Naruto had taken that and come to his own conclusion.

'Hmmm that explains the whole contract thingy… I guess it could also explain my… sixth sense when it comes to people wanting to hurt me.'

The whole sixth sense thing had developed whilst Naruto was in the orphanage. His Nen had developed a warning system in order to protect him from the 'bad' caretakers, cruel people who would come to the orphanage and take out their frustrations on the orphans that no one gave a damn about, and thus his sixth sense had been born. Later on it had aided him yet again when a slave trader had attempted to trick and kidnap him. The man had told Naruto that if he followed him he would show Naruto to a couple that wanted to adopt him. Sensing the man's intentions Naruto had tried to get back at him and once again his Nen manifested to his needs. He had then made an agreement with the man, if the family that he showed Naruto to did not adopt him the man would pay. Of course this was said much less eloquently at the time…

Flashback.

"Huh? A family? Hmmm you look pretty shady old dude, I don't think I trust you." A six year old Naruto purposely said in a loud voice. This was so he didn't try anything funny; they were still in the middle of the street after all. The hunch back man had oily black hair and a nasal voice that really got on Naruto's nerves but that was exactly why it would be hilarious to trick him. The man looked around nervously but tried to assure his young prey.

"W-Why I don't know what you mean. Wouldn't you like to meet them? They are so excited to see you…" He trailed off as Naruto adopted a thinking pose. He was pretending to think about the offer but in reality he was just thinking of how he was gonna dupe the old dude and possibly steal his wallet. And because of that nasty voice he had Naruto decided to kick in the jewels too, it would certainly help in getting the man's wallet away from him.

The naïve blonde had no idea that the man was planning on selling him onto a life of misery, suffering and harsh labour. If he had he would've ran away from him as far as possible. Even with his uncanny ability to feel whenever people had bad intentions towards him it was not powerful enough to distinguish between the levels of 'badness'. If it was possible at the time he would've felt that the man reeked of one of the worst kinds of malice but alas he could not.

Looking up at the man he then spoke the words that would, unbeknownst to him, change his life forever.

"…Okay dude I'll go with you but if you're just gonna try and scam me you'll pay, got it?" To the sad excuse of a human being that simple phrase did not mean much. So without a thought he simply nodded his head and replied.

"Okay, okay kid but trust me you'll thank me later." In his mind he could imagine how much money he would get by condemning Naruto to a fate that was perhaps worse than death. Ironically, at the same time, he had unknowingly sealed his own fate.

The conditions had been met and thus a contract was formed.

However because it was a verbal contract it should not have had much power. Couple that in with the fact that it was vague it made it a weak contract in the scale of things.

But it still proved to be fatal.

Later on after the man had started leading Naruto to the family that was interested in him Naruto had discovered his true to intentions. They had stopped at an alley way and the man turned around with the most evil of grins, it had sent alarm bells off in his head and Naruto immediately turned to run away. The bad feeling that Naruto was getting skyrocketed and at the moment he was incredibly scared.

However as the slave trader made to grab Naruto and spoke his true intentions to hand him over to the highest bidder that he could find instead of a nice family or even to simply scam Naruto of the small pocket change he had, Naruto's Nen activated.

The man had broken the contract.

The Nen that attacked him could've easily been blocked by anyone that was even moderately trained in it but the slave trader was not. And because of that an assault by Nen was equal to being stabbed in the chest.

He keeled over and Naruto in his panic ran away from him as fast as possible. He did not try and comprehend what had happened or how the man had died. The only thing that mattered was getting away from the dead body that was on the ground in front of him. Should he have been caught he had no doubt that the consequences would've made the beatings at the orphanage seem like a nice stroll through the park.

It was because of his panic that Naruto did not notice that someone had seen what had happened. This other man had in fact seen everything that had transpired; from the moment that Naruto had made the deal with the slave trader and thus his activation of Nen when the contract was formed to when the slave trader died due to the Nen that assaulted him. Considering the fact that Naruto did not seem to know what had happened at all he came to a conclusion.

The kid was one of those incredibly rare Nen geniuses.

The man was a hunter who was currently employed by the mafia family that would later kidnap Naruto. He returned the same day to his employer, an ambitious leader of a relatively new mafia family who had his eyes set on the seat of the Ten Don's. He knew it was going to be a hard and long climb but his desire for riches and respect fuelled him. The family leader knew of Nen, but only that it was a freakish power that he could make use of in his climb to the top. Because of this he decided to hire a hunter, people who did incredibly perilous tasks, ranging from capturing notorious criminals, to exploring uncharted lands and hunting down dangerous creatures.

His logic was that the reason these hunters could do all of these amazing feats was because they could use Nen. It was spot on. So when the hunter had returned to him and told him of what he found along with why it was such a big deal the family leader immediately commanded him to find and capture Naruto. His logic in this decision was also correct. Nen users were rare to come by according to the hunter and someone who was a natural genius was even rarer. In his greed and ambition the leader of the young mafia family desired to capture and use that power for his rise to the top.

He could not imagine what he had set into motion, for both the boy and for his own daughter.

Flashback end.

Zeno listened to the story that the blonde shared with him with a keen ear. From it he could already tell a few things that were necessary for Naruto to do in order to activate his ability. The boy only confirmed his suspicions,

"Basically whenever I make some kind of deal with someone whatever it is that was agreed has to happen, otherwise the person will suffer the consequences I guess… something like that!" The blonde finished with a bright grin that showed that he was completely ignoring his vague and bad explanation. The professional didn't really mind since he had basically come to the same conclusion.

Naruto's ability made a binding contract between himself and another person. The terms of the contract were decided upon by Naruto and those terms were not meant to be broken. If they were Naruto's Nen would seek out the person who had broken it and attack him/her. Zeno guessed that the more complicated the terms, the more powerful the Nen assault would be on whoever broke them.

That was a dangerous ability. It was also incredibly unorthodox. Which was precisely why Zeno was going to make use of it.

If he could make the right contract with Alluka there was a chance to perhaps not entirely destroy the 'other' Alluka, the one who made requests and granted wishes in return, but instead to rein her in so that the child would not be as dangerous as she was. In all honesty Zeno pitied her. She was full of potential but so difficult and dangerous to deal with that the family had no choice but to isolate her from everyone, for the family's safety. From what they had concluded there was the possibility that if one wish went wrong, or if they failed to fulfil her requests that the whole family could be wiped out.

That was not acceptable in Zeno's or Silva's eyes so for the good of the entire family they had decided to lock her away. Killua had protested but the needle that Illumi had stuck in him made him afraid to disobey Illumi or the older family members.

The needle was meant as a safety precaution. For Killua not to go against clearly stronger opponents than him. This had the side effect of making Killua afraid to disobey Illumi or his father and grandfather because it would be, in a way, going against them. All of the mentioned people were clearly stronger than him and thus it restricted Killua's actions.

However this boy could be the key. Of course Zeno needed to test exactly the lengths of his ability, the drawbacks and restrictions or conditions to it and ultimately whether it was safe and powerful enough to be used on Alluka but it was a chance nonetheless. The old assassin had been trained to always put the family first and right now taking Naruto and potentially fixing Alluka's problem was definitely putting the family first. So he banished any other doubts that he had. Right now this was the best option. An opportunity like this did not present itself easily or more than once.

Naruto on the other hand thought carefully at the opportunity presented at him. In all honesty he wanted to take the chance but going in blind and without any safety measures was incredibly risky. The first time he had gone along with someone's wishes it had almost gotten him killed. It was through sheer dumb luck that Naruto had survived that situation with the slave trader. Not wanting to make that mistake again Naruto decided to make the old dude form a contract with him so that his own life would not be put in peril.

It was then that he realised his mistake. He had already explained how his ability worked to the old man so if he wasn't going senile, which by the way he managed to sneak into the mansion without anyone finding out, and also by the way that he wasn't really all that worried about getting caught in the first place suggested otherwise it meant that he wouldn't be tricked into making any deals with Naruto!

He flopped down on the bed with a rain cloud of depression forming over his head as he mentally wailed at his foolishness. Zeno seeing this only chuckled and thought to himself that this should be a fine first lesson for the boy.

Telling your opponent or anyone that you were planning on getting the drop on how your ability worked was incredibly stupid and could be paramount to suicide. From the story that the boy had told him Zeno had concluded that even though he was curious to the offer and was willing to risk it he wouldn't do it carelessly and would most likely want to make a contract with him as a precaution. Something along the lines of 'don't let any harm fall upon me whilst I'm in your care and I'll take the job' If Zeno failed to comply with the term then any number of things could happen. It could range from the boy's ability being blocked from being used in the way he wanted to, to Zeno himself being assaulted with Nen because of his failure to follow the terms. He wasn't too worried about the second one as he had guessed that with a powerful ability like that there had to be some restrictions to it. Zeno's old and sly mind had already thought up of a few but the one that he thought would be most likely would be that the Nen assault from breaking the contract would only be either as powerful as the contract was or as powerful as Naruto, the one who had established the contract, was.

He was sure that he could therefore overcome the attack but the first scenario was the most troublesome. If that did happen then any chance of fixing Alluka's problems would be gone and Zeno couldn't allow that to happen.

At the same time however he did not like the idea of simply kidnapping Naruto and forcing him to do their bidding. Whilst there was a chance that it could work if Illumi got his needles involved there was also a chance that Illumi's control over Nen would not be effective enough or he simply wouldn't be careful enough and would therefore harm Naruto. Usually whenever Illumi used his needles on someone because of his powerful Nen the people affected would lose themselves, brain functions included. Was it possible then to command the blonde to make a contract whilst under Illumi's control? The answer was about 50-50 but it was an unnecessary risk in Zeno's mind.

The thought of threatening Naruto into it did not cross his mind and later Zeno would look back on this meeting and ponder why.

Thankfully whilst Zeno was thinking of using Illumi's power he was not seriously considering it and more importantly he did not want to go through with it at all. He was simply running scenarios in his mind as he was wont to do whenever a tricky situation presented itself. It was because of this that Naruto's sixth sense was not triggered and thus his trust in the old man was not broken.

It was a key event in their meeting that both had seemingly overlooked.

The old assassin finally decided to get the show on the road and thus stepped forward,

"Kid if you want to come with me that's fine. I don't even mind signing a contract so you have peace of mind but let's leave already." Zeno broke the silence in his casual tone of voice. Naruto looked up from the bed and stared at him with a puzzled expression. Thoughts of whether Zeno had read his mind briefly raced through his brain. After all he was still new to this whole Nen thing and from the way Zeno had explained it sounded incredibly awesome so it was possible right? Humming in thought when Zeno didn't either confirm or deny his thoughts Naruto shrugged before he went to work.

He got off the bed and sat down on the floor. Letting his Nen take control as he did whenever he wanted to activate this ability Naruto was covered in powerful aura that began condensing and then manifesting itself into particular items. First a black quill materialised onto his right hand as then a bottle of ink materialised onto his left. Next a role of parchment appeared on the space in front of him and thus all the requirements were set. Naruto in fact did not need to do this. Just as he had done before he could simply make a verbal contract. Even if he feared that would not be enough he could just ask for paper and a pen and write down a contract with it.

The reason however was because Naruto, as he had mentioned earlier, had been playing around with his ability. What he had accidentally discovered was that if he wanted to make a contract as strong as possible this was the way to do it. At the time Naruto had simply had the thought of 'I want to the most powerful contract' He had done this at night in his room not too long after he had passed out from having tried to make more than three contracts a day. The reason he had tried to experiment was because he wanted to see the limits of his ability and what he could really do with it. In response his Nen manifested in the most appropriate form and thus he had been able to Conjure the quill, ink bottle, and role of parchment. He had not told anyone about this discovery because they would undoubtedly make him do more work and make him work harder. The problem was that he didn't want to do more work firstly and secondly the act of actually conjuring these things and then making a contract with them was immensely tiring.

In this situation it was necessary. Naruto basically wanted the best insurance policy he could afford at the moment and this was definitely it. It was worth being exhausted afterwards if in the long run it would keep him alive.

Zeno on the other hand could not believe his eyes. He had seen many things in his life as an assassin however this had to be in the top ten at least. He had earlier guessed that Naruto had incredible Nen potential and the feat he had just performed completely confirmed it.

This kid was a monster.

From his explanation of Nen to Naruto and Naruto's reactions he could tell that the kid really had no idea what Nen was. This meant that the kid was purely doing this on instinct, his Nen simply abiding to his command and manifesting itself in the most powerful way possible at the time. It was truly astonishing.

'What a fearsome kid…' was the conclusion that he reached.

After twirling the quill in his hands a couple of times Naruto grinned,

"Let's get to business old man." The blonde declared. Sighing at the devilish grin the youngster in front of him was giving him Zeno only replied,

"What are the terms?" The old assassin stared at him as Naruto made a humming sound and then began writing,

"You are not allowed to harm me and neither are you allowed to let harm fall upon me whether through an indirect action, decision or lack of action at all. Whilst under your care or the care of any others you pass me onto any harm that happens to me will also happen to you. In return I will fulfil the job you proposed to me to the absolute best of my power no matter how long or what lengths I have to take in order to do it."

Zeno hummed in surprise. That was a pretty airtight contract; the downside that he could immediately see was that the last two lines could put Naruto into quite a bit of a bind. He guessed however that it was compensation for the line that if any harm at all should fall to the kid Zeno would receive equal harm. The old assassin did not think that a contract could be worded like that and it was surprising in all honesty. This meant that the kid was pretty much not to be touched whilst he was working on completing Zeno's request. In a way it made him nigh invincible against Zeno and to an extent against anyone that cared for the old assassin's fate should they lay a hand on Naruto.

"Now all ya need to do is sign here, I've already signed it myself." Naruto instructed as he turned the parchment over to Zeno and the quill floated over to the old man. Grabbing it he walked forwards and read the contract again. He then looked at the name that was signed.

Naruto Uzumaki. It was kind of a strange name but he didn't pay much mind. To the left of where the name had been signed it said Maker:

Beneath it was a space where Zeno could sign his name. Next to it and again in bold writing it said Signer:

He went ahead and signed his name down with the quill and then handed over the contract to Naruto. Naruto checked it over and hummed in satisfaction with his work and Zeno noticed from the corner of his eyes that the quill and bottle of ink disappeared back into aura before being absorbed into the seven year old. He then began to feel a massive build-up of Nen coming from the youngster in front of him but he didn't even flinch as practically a torrent of Nen burst from him in a white flood of energy.

From Naruto's lips words then echoed,

"Deal with the Devil: The Contractor, activate." And Zeno grinned.

It was the start of a beautiful relationship.

Well there you go I fixed the chapter not being finished. If you're reading this and are thinking what the hell is he talking about then don't worry about it I just messed up at the very end :'D. Anyways thanks for reading and feel free to leave a review ;)