Disclaimer: Hunter x Hunter characters & places belong to Yoshihiro Togashi (hopefully I spelled the name right) and My Hero Academia characters & places belong to Kohei Horikoshi (I'm bad at names, please tell me if I spelled either of those wrong). Some plot elements may be taken from MHA, but the story itself belongs to MarkTwainTwo (hi!).

Note: Comments / reviews give me serious motivation. Whether you like or don't like it, if you have time let me know your thoughts!

Killua

As it turned out, portal villains were really good at running away without leaving a trace.

Killua experienced this first-hand when he arrived back where he'd first landed in that world and found exactly zero indication, save for the crater in the sidewalk, that anyone had been there. Any traces of their auras just up and vanished, which he should have expected but was still annoying. Furthermore, as soon as he'd done some digging (read: threatening) in the underworld, he'd found out that up-and-vanishing was a normal occurrence for the "League of Villains". This meant that no one could tell him where to find the portal villain, though he did learn the guy's name: Kurogiri.

It was approximately two in the morning, and Killua was sitting at an underground bar and brooding in the midst of rowdy groups of criminals. No one had bothered him, both because of the unnatural shadows around his face and hoodie and the fact that he was using In and most of them didn't notice him in the first place. Their eyes slid from the seat on his left to the seat on his right without really seeing him.

He was trying to decide on the best course of action. Should he wait for the League of Villains to find him, as he was sure they would (since they had been the ones to portal him into this world)? Or should he try to find them, which would be less wasted time waiting? Would looking for them cause them to assume he was a threat and hide, thereby making it take longer to locate them?

Breathe, Killua.

Concealed presence or no, you'll be noticed if you accidentally shatter the whole freaking counter. So stop gripping it so tightly, baka!

He forced himself to relax. Alluka and Nanika and Gon were probably fine. Kurapika and Leorio were probably fine (not that he cared). Hell, maybe time passed differently on this planet and he'd be back before they even realized he'd been gone.

It's fine.

I'm fine.

Everything's fine.

"I'll only do it if we split 50-50, and that's that," a girl's voice said in a harsh but petulant whisper.

That particular statement had only caught Killua's attention because it was close and didn't sound remotely drunk despite being in a criminal tavern. He didn't particularly care to continue listening until a man responded, "Very well. I'll see you at the arena in an hour. Your opponent will be strong, with as strong as your listed Quirk is. You'd best not disappoint."

It took a large dose of Killua's assassin training not to turn around and stare, or start grinning like a maniac.

Arena? By the sounds of it, a fighting arena? Where kids (that girl's voice was definitely a girl, definitely young) could earn money?

Hell yeah.

Unknown (and rather unimportant)

The barkeep stared in astonishment as a little boy with a face covered in shadows appeared on one of his stools.

"Can I have that one?"

He was pointing at a bottle of very heavily alcoholic substance.

"Uh..." the barkeep said. "Aren't you a little young?"

"Don't worry." The boy smirked- the barkeep could see that much. "I'm immune. Besides, I'm not the one who's gonna be drinking it. And I can pay. So give it."

There was a pause.

"Unless you wanna die?"

...

And a minute later, a sharp-clawed boy with a hoodie and a bright smile hopped off his stool and trotted away from the horror-struck barkeep.

Silon (an OC, who is also rather unimportant but needed a name)

Silon liked to view himself as an easygoing guy. Not a risk-taker, not a hothead. He was just one of Giran's employees, sent out to recruit possible fighters who weren't deemed important enough for Giran himself. He didn't like getting involved in conflicts, which was ironic as his purpose was to recruit others who would initiate conflict.

When the second kid that day (the first being the girl Toga) sat down across from him, therefore, he didn't tell him to scram. Instead, he gave the boy a once-over, then said, "Did you need something from me, or are you hoping for charity?"

The boy's head was tilted down, so all Silon could really see was his hoodie. Then a pale hand deposited a bottle on the table and pushed it over to Silon, whose brow lifted in surprise.

When the boy didn't say anything for several seconds, Silon grabbed the bottle and popped it open, then sniffed it. It didn't smell like any poison he knew, but...

Just to be safe, he pretended to pour it into his glass, but at the last second used his Quirk- Sleight of Hand -to switch it out with his own bottle. He didn't know what the boy wanted, but his time as part of an information broker's network taught him that it was better to know than not to know. And he had a feeling the boy wouldn't tell him anything until he drank.

He downed half his glass, then met the boy's eyes.

Or tried to.

The boy had looked up, but all Silon could see were thick shadows above the mouth, obscuring most of the boy's features. Nevertheless, Silon felt the boy staring at him with unnatural coldness, and the mouth betrayed no emotion.

"I want to speak with the top villain broker in your network," the boy said, quietly but clearly. "You will give me his name and address."

"Or what? You'll kill me? He never offers a job to anyone who kills an employee of his." Perks of the job. Silon had decided to work for Giran largely because of the safety the man offered. He couldn't risk his daughter ending up alone and penniless, but a lot of people wouldn't hire someone who'd been to jail before.

Two pale hands half-covered by the dark blue sleeves clasped together on the table. "He'd never know. After all, this particular poison has no effects that wouldn't be attributed to too much alcohol."

Silon smiled.

"Unfortunately for you, I didn't actually drink from the bottle you gave me. And I don't help people who try to kill me. Sorry kid, but you need to leave, before things get ugly."

There was no disappointment, fear, or anything that he'd expect from a little boy after those sentences. Silon's expression faltered a little as the boy returned his smile- but his was that of a predator, all teeth and confidence.

"Unfortunately for you," he said, "the bottle I gave you wasn't the one I poisoned."

As if on cue, Silon felt his muscles seize up. Then they went weak. Numbness spread from his fingers and toes, until he couldn't move or feel his body. Almost in slow-motion, he plummeted face-first into the table. Suddenly he was struggling to take in air.

The boy's soft, mocking voice was right next to his ear. "I've got the antidote right here. Give me the name and address. And while you're at it, I want to know his Quirk, too."

Silon could no longer think straight. If he could, he might've tried to mislead the boy.

Dying can do weird things to your brain.

"Giran," he gasped out, and rattled off the address that the broker usually occupied. "Quirk's Muddiness... 'e can give... 'mnesia by... touchin' someone's fore'ead."

The world was going fuzzy, and he couldn't even feel his face. Would he die here? Would his daughter be orphaned despite his best efforts?

Something pressed against his lips. A glass of... something. Without thinking, he gulped down the liquid.

Almost immediately, the world came back into focus and the weight on his chest lifted. His arms and legs started to tingle as feeling came back into them, followed by his fingers and toes. He groaned, and struggled into a sitting position.

"Are you alright, laddie?" An old man was standing next to him, giving him a small, friendly smile. "A little too much to drink, eh?"

Silon glanced around him again, listening to the chatter of the bar and scanning the faces as the old man hobbled away.

The boy shrouded in darkness had vanished.

Killua

He probably could've used the man at the bar to set him up for a fight, but Killua knew from experience in his own world that plans made with subordinates would often go awry. He needed to speak to the top dog- the one who could take an interest in him, and get him interesting opponents.

So he'd transmuted some of his alcohol into a version of the curare poison, and done the same with the man's alcohol too, using In to do so without him noticing. That way, no matter which bottle he ended up drinking from, he'd be drinking poison (and that man would drink one of them- in Killua's professional opinion, he was an idiot).

Getting poison and antidotes was so much easier with Nen.

...And so was moving quickly.

Killua deactivated Godspeed just as he arrived outside Giran's business building: a typical ramshackle, nondescript building that might have been an apartment or store once. Its crumbling bricks were in the same color and state as all the other buildings around, and half the windows and doors were boarded up. Killua, however, being the assassin that he was, noticed that the non-boarded-up windows were placed strategically so as to still provide the best viewing angles. So maybe this broker wasn't all that dumb.

Too dumb to realize how incompetent his guards were, though.

He slipped past the guards at the door and gave the ones in the hallway chop to the necks. There were two standing outside the door that presumably led to Giran's office, and here he slowed enough to give them a little wave.

"Hey," he said. "Take me to your leader."

Giran

Three knocks on the door.

Giran looked up, curious. He'd told the guards not to bother him unless it was important. "Leave a note."

"No paper," came the reply. So whatever or whoever it was, it wasn't too dangerous. He reached under the desk anyway, pulling open a drawer and resting his hand on the FN handgun inside.

"Come in," he said cautiously.

The door opened slowly, revealing his two guards and. And. A little boy, apparently.

Apparently, because although the stature was small and the clothes suggested it was a boy, he a) couldn't be sure they weren't female and b) couldn't be sure they weren't an old man in disguise, because most of the face was covered in thick shadows cast by the dark blue hoodie.

"I'm going to assume you're here to do business," Giran said after a pause. "I'll warn you, though, that if your business is to kill me, I have measures in place to make your life hell afterwards."

"Nice ultimatum," the (probably-)boy said, smirking. "And you didn't assume you're stronger. That gets you a couple favor points, old man."

Giran frowned. Old man? As much as he was a little insulted, it also probably meant this actually was a child. He relaxed his grip on the gun, but didn't let go of it. He locked eyes with his guards over the (probably-)boy's shoulders, and nodded. They nodded back and made their exits. The second closed the door behind him, leaving Giran and the probably-boy alone in silence.

"Luckily for you, I'm not here to kill you," the boy said. "If I was, you'd be dead ten minutes ago."

He paused, and Giran got the feeling he was being studied.

"I'm here to get a sponsor for a fight club." It was said carefully, as if to gauge Giran's reaction.

Giran pursed his lips. He should have expected that, but- a child? Then again, one of his henchmen had texted him not too long ago to say a teen girl had signed up to fight, and although uncommon it wasn't unheard of.

"How do I know you can fight?" he asked.

The boy shrugged. "Would I be here if I couldn't?"

"What's your Quirk?"

He gave a s***-eating grin. "I'm Quirkless."

That made Giran's brow raise. Not only a child, but a Quirkless child? But wait... "Those shadows aren't just from the hoodie, kid."

Said kid scowled. "Don't call me a kid."

"My point stands."

There was a pause. Giran waited.

"It's not a Quirk," he said finally. "You'll have to trust me on that."

"I don't even know your name," Giran countered, "Though clearly you know mine, as well as where I work and who I am. I'm probably right in guessing that you also know my Quirk. How should I trust you?"

There was another pause. And then-

"How can I prove it to you?"

Giran thought about that. He didn't need to trust the boy not to betray him, because he had a feeling that "you'd be dead ten minutes ago" wasn't just a brag. If he'd wanted to kill or hurt Giran, he'd have done it already. So he didn't need to trust the boy not to betray him, he just needed to trust that he could fight well. Then it wouldn't matter if he was a child, because then Giran could rid his mind of the matter, thinking of him as just another bag of money.

"Prove that you can fight," he said, leaning forward and clasping his hands on the table, abandoning the gun. "There's someone I want dead. If you can kill them and bring me sufficient proof, you're hired."

"Deal," the boy said immediately, sticking out his hand.

Giran was taken aback. He'd expected the boy to at least hesitate. If possible, his brow rose even higher. "You don't want to know who it is? What if I asked you to kill All Might?"

"Are you trying to convince me not to kill your target?" the boy drawled. "I'm not worried. Just take your own deal, old man."

It was Giran who hesitated then, but eventually he took the offered hand.

(It was a very small hand.)

He withdrew and shuffled through his desk drawer until he found a folder. The boy stuck his hands in his pockets, and even when Giran slid the folder across the desk he didn't remove them.

"This is the target," Giran prompted, wondering if the boy was waiting for him to open the folder or something.

"I don't need to know about them," the boy said tonelessly. "Just tell me the name and address."

Giran stared, then shook his head, taking the folder back. "His name is Yotsubashi Rikiya, but he goes by Re-Destro." He rattled off an address that the man was likely to be found at. "I think he'll be a problem for me in the future, so-"

He stopped. He'd blinked, and the boy was gone. He blinked again, then noticed the door click shut.

A small breeze rustled through the room.

Re-Destro

"Well, get it done!" He growled into the phone. He listened, then a slow smile spread across his face. "You don't think you can? Well, why don't you take a look at the building to your right, fourth floor." He listened again.

He was still laughing when he hung up on the screams coming from the phone.

"Oh well," he chuckled to himself. "I guess I'll just have to find another to threaten..." He turned on his heel, still laughing.

Then he wasn't laughing.

Then he wasn't living.

...

There was a sigh from the shadows. "That was a little too easy." A hand reached out, claws retracting into soft, pale fingers. It grasped Deceased-Destro's hair. "Hmm... I wonder if this would do as proof."

Giran

It had been a tense several moments before he was able to get back to his work. Even then, he glanced at the clock and then the door every few minutes. He knew the boy wouldn't be back for a while now, if ever, but he kept feeling something foreboding in his chest.

Maybe he shouldn't have sent a child to kill a dangerous villain? No, that wasn't any worse than letting that kid fight. If he couldn't handle the villain, he would probably be dead soon anyway. Although, it was a very dangerous villain...

Another wind rustled through the room, accompanied by what might have been a flash of electricity but was probably a trick of the light. Giran's office door clicked shut again, and the guards outside gave twin shouts of surprise. They burst through the door, and froze, just as Giran himself had done as soon as the boy was moving slowly enough to be visible again.

There was silence.

Killua

He held the man's head out in front of him by the hair. Its expression was frozen in a look of horror, and it was quickly loosing blood so that the skin looked papery-white. That lost blood was dripping into a growing puddle on the floor.

"Well?" he said, raising an eyebrow that he knew Giran couldn't see. "Is this enough proof?"

Giran

The boy had never even taken his right hand out of his pocket.

Note: Yes, yes I did just kill off a major character of later MHA episodes. But, I do have a reason. A couple of them! 1) Giran needed someone important for Killua to kill. 2) This shows just how much power Killua has in this universe, that he is able to change the course of the future plot (not that they know that).

I'll try not to kill any other major characters before their time...

Even though it's fun...

*sighs*