A Spy and a Fighter

Aizawa pov

Dead end. It had been over a month since Killua disappeared and almost all the heroes gave up searching, the police as well, only detective Tsukauchi, All might, and at times Aizawa kept searching, hoping to find the young boy but they always end up in a dead-end. He disappeared; he had become a ghost; it was like he never existed in the first place. No past, no signs that he was alive. He could have been kidnapped, he could be dead and they wouldn't know.

Aizawa took a deep breath to shake these thoughts out of his mind. For five months now he had been on an undercover mission in the underworld. He had two more months to complete his mission before U.A. started, he didn't have enough time and few people suspected him. If his cover were to blew up, then God help him, he was in a place full of villains he would die in an instant.

He chose a sit in the front, he usually sat at the very back of the stadium. But tonight's fight was Shadow against a low-level criminal. Shadow was a mystery in the underworld, he appeared out of nowhere, Aizawa tried to collect information about him but there was nothing, the only known thing about him was that he was one of Giran's fighters. Other than that, nothing, no backstory, no criminal record, no name, unknown quirk. He had seen his fights, he won with ease and he never, not even once used his quirk. Just like Killua, he was a puzzle.

Killua and Shadow maybe they are both pieces of a puzzle, maybe they are the same person, or maybe they are completely unrelated and his brain tries to ease himself from the guilt that came with losing a kid that was on the brink of death. Still, it's clear that Shadow is young, these fights are probably because he is in need of money, he finishes the fights fast, he doesn't drag them out like he doesn't want to fight. Perhaps it's something else.

He looked at the young boy in the cage as he dodges every attack with his hands in his pockets, he looked at his face. He was surprised by what he saw, boredom was written across his face. Even if the guy he was up against was a low-level villain, he was still a villain, three times of Shadow's size. But the kid looked like he was dying of boredom, he was trying to drag the fight out, probably because he always finished too fast at the people were starting to get bored of how fast he wins.

Shadow caught his opponent's fist, standing his own ground. Superstrength that was his opponent's quirk and Shadow simply caught his punch standing his ground and not moving one inch. A wave of wind blew at the cage from the power the punch was about to land on the boy, but the boy's hand was unmoving like a thick layer of ice, it stands strong with no cracks. Maybe that was the boy's quirk as well, superstrength.

As he held his opponent's hand, he moved his other hand and landed a very powerful punch that caused the bigger guy to fly to the other side of the cage. He tried to stand up, shaking with effort. Shadow's expression didn't change on the sight, he still looked bored to death. He sighed heavily and disappeared from his spot only to appear above the bigger guy on the other side of the cage, he landed a very powerful roundhouse kick on the man's face resulting in a deafening crack as his nose broke and he fell unconscious, resulting to Shadow's win.

The crowd erupted in cheers as this was the longest fight, they saw from the young fighter. Aizawa could tell that the boy still hold back a lot. He stared at the young boy intently, he noticed how his black hair was closer to a dark ash color, his stance seemed to be relaxed but that was far from the truth, Aizawa saw that he was still in defense, ready to encounter anything that was thrown in his way.

The young boy's eyes scattered on the crowd, analyzing every person inside the stadium until his eyes finally landed on him. At that very moment, Aizawa saw the glint of intelligence at the young boy's eyes telling him that he knew exactly who he was. He had noticed as the boy kept stealing glances at him during his fight, at the moment Aizawa thought nothing of it, but now, now it was obvious that there was more to the glances than he first thought. And fear was the first thing he felt at that very moment, his cover was blown and there was no way to cover it up. Few words from the boy and then everyone in the stadium would be attacking him. He was prepared for the worst, a possibility that never came. Instead, the boy turned on his heels and walked away from the stadium disappearing in the shadows. Needless to say, Aizawa was confused, very confused.

Killua's pov

In the spawn of a month, Killua managed to become one of the most popular fighters in the underworld. He had decided to go by the name Shadow, in reality, though he didn't get the chance to choose as one day he was introduced by that name. He was confused in the beginning, then he decided that he didn't give a crap about his fighter name as he would only be fighting until he gets a decent job and therefore allowed it. Plus, it was somewhat of a badass name so, why not?

Giran: Hold up kid, before you go back, the league contacted me again, told me to ask you to reconsider their offer.

Killua: There is nothing to reconsider. They've already asked me three times and my answer is still the same, so do me a favor Okuta and tell them to fuck off. Killua told him with annoyance and frustration rising in him. That was the fourth time they asked him to join their Phantom Troupe parody, it was starting to annoy him to no end.

Giran: First, how did you find out my name? Second, why don't you consider it?

Killua: Your name isn't a national-level secret; it was rather easy to find out. As for the league, I'm not interested in the least. Don't ask why, I won't bother to explain myself seeing as there isn't even a reason to do so. Giran let a heavy sigh of registration escape him.

Giran: I'll inform them but no promises, they are suppressive.

Killua: Yeah, I figured as much. They started pushing up my buttons though and I can take so much. Killua sighed and looked over Okuta, he knew that the older man had more to say than just be a mailman for the league of villains.

Giran: So, superstrength. That's your quirk, I would never have figured it out. You look more like speed and agility rather than power. No offense.

Killua: Right, superstrength. He said with a rather impassive voice. 'That's just lame, but whatever let's just roll with it' Is there something else you want, cause I gotta run.

Giran: Nope, I'm just glad I finally found out your quirk. Giran said while grinning.

Killua: Right, I'll see you next time. Killua told him and disappeared into the shadows.

'Aizawa' Killua's thoughts were flooding with the man that saved his life, well with one of the two.

He remembered the first time he saw him in the underworld. It was on his third fight, as he walked in the stadium, he sensed a familiar presence and immediately scanned the crowd for said presence until his eyes finally landed in a very familiar and sleep-deprived face. After his fight, he decided to follow him and he successfully found out about his undercover mission. He let it be as he seemed not to know who shadow really was and that he wasn't a danger to his plans. And perhaps he was also a little worried for the man, after all, he did save his life, he felt like he was indebted to him. So, he still kept an eye on and for him.

He noticed as people became more and more suspicious of Aizawa and decided to confront him, sure he would have to blow his cover-up, but he had decided he liked the guy. That and he was in his debt… All might's as well and the doctors. 'I'm in debt to three different people since day one in this new world… way to go me' He thought as he ran through rooftops towards the very familiar aura.

During his time in this world, he found out that people didn't possess nen therefore if he were to use his nen against a non-nen user nothing would happen, he wouldn't have to worry about fully opening the aura nodes. That is if he decided to go all out and use nen in the first place.

Aura thought was still distinguishable since it's the life energy produced by all living bodies and it's vital for survival. On the other hand, there were quirks, he tried to use Gyo when he saw heroes and villains using their quirks but he saw nothing that indicated the use of nen. Quirks and Nen were different, and there was nothing similar between the two.

Killua came to a halt when he reached his target, Aizawa was walking in an ally (A/N cliché much?) and he was alone, this was his chance. He didn't want Aizawa to die and if he had to uncover himself to save his life that was fine with him.

He jumped off the roof and landed soundlessly behind Aizawa, who was still oblivious to his presence.

Killua: You're going to get yourself killed if you continue this mission… Zombie. Aizawa turned his head to the newcomer's very familiar voice and saw Shadow stand Infront of him. He quickly registered the young fighter's words and grinned in the familiar nickname.

Aizawa: It's been a while… Killua.

Killua: Indeed. Killua replied as he took off his mask revealing his face. People are into you. It was a statement that was known to both of them. You're going to get killed if you don't stop. He finished while staring at the tired-looking man.

Aizawa: I can't, I have a mission

Killua: Is your mission more important than your life? Killua asked with a bit of annoyance at this man's ignorance.

Aizawa: When it involves innocent people's lives then yes, it is. Besides, I'm more interested in you. what are you doing in the underworld?

Killua: First of all, you can't just compare your life with other people. Second of all, it's rather obvious really.

Aizawa: Let me guess… money? Aizawa asked while raising his eyebrow at the boy.

Killua: Obviously, I'm a runaway teenager. Also, you ignored the first part of my statement.

Aizawa: For obvious reasons. By the way, do you know your hair color is starting to revert back? Also, Superstrength I thought you didn't have a quirk. Killua looked at Aizawa suddenly an idea rising in his head, a dump idea, but for some reason, he felt like he could trust Aizawa, no… he already trusted him.

Killua: I wasn't planning on keeping them black forever, I mean I do want to enter U.A. plus I don't have Superstrength but because of my training I am able to lift About 20 to 25 tons. Aizawa looked shocked at the kid, not only he said he didn't have a quirk but also told him how much he could lift with just his physical training, for a quirkless kid to be able to lift so much, a weight that should be impossible for normal people to lift. He could only imagine what the kid's life was and he shuddered at the very idea. Still, the kid showed him that he trusted him by sharing information.

Aizawa: Why did you run?

Killua: I needed information, money and to learn how to read and write. I accomplished all that I wanted. Now I only have one thing left to do and that is U.A. Aizawa smirked at the boy and the irony, an underworld fighter that wants to become a hero. Still, he understood where the kid came from, money was inessential especially since he was a runaway with no money and a place to… wait.

Aizawa: Do you have a place to stay?

Killua: Yeah, I rent a small apartment. Why?

Aizawa: You are fourteen…

Killua: Yeah so? Killua was honestly confused with Aizawa right now, also the zombie managed to pull him out of topic somehow.

Aizawa: You do realize you are technically a criminal for fooling people to rent an apartment, right? 'So that was it, huh, I was confused for a moment'

Killua: Well excuse me, people won't just rent their houses to fourteen-year old's I had no choice but to lie, also I needed money and fast, no decent job would do me any good. Killua said defensively and Aizawa sighed, it felt like he sighed a lot more lately.

Aizawa: I'm not blaming you kid, I understand. But renting an apartment takes a lot of money and you will eventually have to stop with the fights what happens then?

Killua: I don't know I'll figure something out. 'I'm definitely going to regret this later…' Aizawa thought

Aizawa: How about staying with me? That way you can stop what you're doing. Killua grinned at how the conversation went in his favor and Aizawa simply thought 'shit' as he saw the cat-like expression on the young albino's face.

Killua: How about a deal then? 'I've fallen to his trap haven't I' Aizawa thought already regretting his decision.

Aizawa: What kind of a deal? He asked narrowing his eyes and trying to look intimidating.

Killua: I stay at your place in exchange for me becoming your spy.

Aizawa: Forget it. Aizawa replied in a heartbeat.

Killua: You didn't let me finish… I'll tell you my story, who I am, who I used to be. In the end, it's up to you whether you trust or fear me. But like it or not I do have the power to pull you out of that shithole with or without your consent. Trust me this deal is in your best interest not only you get to solve a mystery which is me, but you will also have the ability to keep an eye on me plus an underworld spy in a fighter's position. Also, I might be able to gather information about the league of villains.

Aizawa: You're a kid.

Killua: I haven't been a kid since I was younger than a toddler… You don't have an option you either take the deal and win something out of it, or you leave it and lose everything. Answers, mission, information, and me. What is it gonna be Shōta? As Killua said, his expression became serious and left a little bloodlust out to be more intimidating. Aizawa back away in reply to his bloodlust, but quickly regained his posture and senses.

Aizawa: Why do you want to be a hero?

Killua: Because I already failed to protect someone I cared about, and now I want to be strong enough so she can be proud of me and be able to do what I couldn't before. Being a hero isn't about the power it's about the ability to protect. Aizawa smiled at Killua's worlds, he could see the determination in his eyes. He knew the kid had a dark past, how dark he wasn't sure. But he wasn't a bad kid, he was someone who he could accept no matter his past, he could see the pain and the kindness behind the coldness in his eyes.

Aizawa: I want you to tell me your story, I won't accept anything but the truth.

Killua: I wasn't going to lie, but you can't tell anyone else. Also, no matter how crazy my story is I swear I won't lie, not about my past, my family, and not about the place I come from. I trust you Aizawa you remind me too much of someone not to.

Aizawa: Alright, follow me. Killua followed Aizawa to his home getting more nervous with every step, sharing his story he only did that with his best friend, and then there was the possibility that Aizawa might never believe him. It was a crazy story but it was his nonetheless.

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Aizawa stared wide-eyed at the boy sitting in front of him, Killua had sworn to tell the truth and only the truth and Aizawa believed every word. His family, his training, his previous occupation, his adventures, and the obvious changes that came with them, his sister's death. He believed everything. As crazy as it was it made sense, but it was still hard to keep it down, Killua was from another world, he was brought here by his sister's sacrifice and she was the reason why he wanted to become a hero. He was at a loss for worlds. He wondered how could he still smile after all that? His life was a living hell since birth, he was forced to kill, forced to grow up instead of being a child. Then he found happiness with friends to get ripped off it, the kid had suffered more than it should be possible, and yet he still smiled. Sometimes fake, he noticed but sometimes not, sometimes it's a sincere smile. That was the second time they talked and during that time he only grinned and smirked but there was this one time when he smiled, truly smiled, no matter how small it was. Even if it was hidden Aizawa saw it. And he could see right now the boy barely hold his tears away.

Aizawa: It's okay if you let your Memories sneak out of your eyes and roll down on your cheeks. (A/N this is a quote I found on Pinterest couldn't resist. Also, I'll be using quotes at times… be prepared for fluff, sadness, and … Karma?) With those words Killua lost his self-control and became a crying mess unable to stop his snobs, Aizawa moved closer and tried to soothe the child. He doubted if Killua knew what comfort meant but he was more than happy to show him. Eventually, Killua cried himself to sleep and Aizawa carried him to the guest room that would soon become Killua's room.