I was talking with my beta Aori, had a flash of inspiration that I was too lazy to write out, and then Aori nagged me until I wrote this the next day. She kindly beta-ed it too. You can thank her for this.

"No, Killua," his older brother said when several seconds passed and nothing happened. Four-year-old Killua looked up as Illumi tapped him on the shoulder. "Like this," he said patiently, extending his hand out to demonstrate how to do it again.

The morning breeze drifted over them, rustling Killua's hair and bringing along a sweet scent in the air. Killua ignored it in favor of watching Illumi's hand, drinking in its every movement with all the stubborn determination of a petulant child.

The next time when Illumi was done and looked over to Killua, he knew how to do it. His hand flashed out, and he stared at it, willing it to change as he had seen Illumi's did.

It obeyed.

Killua let out a strangled cry as his hand remade itself, until its nails grew into claws, its fingers muscled with protruding veins, and its bones cracked until it was reborn into steel.

It hurt, but it also flushed Killua with pride when he saw.

He turned to Illumi, grinning widely. "Illumi, Illumi, look, look! I did it!"

On Illumi's normally blank face, there was a tiny smile.

"Good job, little brother," Illumi said, reaching out and ruffling his hair. "Now, go hunt." He gave Killua a little push in the shoulder.

Killua nodded eagerly, sniffed the sweet scent in the air, and went after the bleeding intruder that got away from their dog Mike in the garden.

That day, for the first time, Killua reached the target before Mike.

He still remembered how satisfying it was to crush the beating heart with his bare hand.

Killua's eyes snapped open, his breathing deafening to the trained ears of an assassin.

There was a rustle in the bunk below, followed by the creaking of the ladder. Killua forced himself to not react, and found comfort in the sound instead. Assassins would never move so nosily.

A few seconds later, a head poked up. Even in the darkness, Killua could see Gon sleepily rubbing his eyes. "Killua?" he said, bemused and questioning at once. "You okay?"

There was something uncanny about Gon's instincts and perceptiveness, despite the fact that he was normally oblivious borderlining idiotic. Killua had grown to appreciate that about his friend.

Killua shook his head. "It's nothing, Gon," he said. "Go to sleep."

Gon yawned, before nodding, taking Killua's words at face value without any question. "'kay, goodnight then," he said, and then he was slipping back down the ladder. "I'm here if you need me."

Instead of saying what was in his mind, in his heart - 'That's all I need' -, Killua merely murmured back, "Goodnight, Gon," and waited in total darkness until Gon's breathing evened out. Then, he said, "I know you're there."

There was a flicker in the corner of the room, a movement too quick for Killua to follow, and then the Arcobaleno was on the edge of his bed.

"Reborn," Killua said.

"Not going to try to kill me today, Killua?" the hitman asked, his eyes too knowing even in the darkness.

"I thought I would try sleeping according to bedtime just this once," Killua replied with flippantly.

"Ah, Mito-san," Reborn said, understanding in his tone, and both of them shuddered in unison. They hadn't forgotten about the time they went camping in the wood ("Training," Reborn said, in a tone so different from Illumi's) and Gon returned with a broken arm after stumbling into a mother bear with its cub. Reborn was yelled at for not watching over him, and Killua, for sweet talking her into letting them go. It had not been pleasant.

"Are you going to creep around since I'm not going after you today?" Killua asked blasély. Too blasély, he could tell, when Reborn's eyes sharpened on him again. Beneath his gaze, Killua felt like all his secrets were laid bear. Reborn wasn't known as the Strongest Hitman for nothing. He saw everything.

"Sure, why not?" Reborn said after a moment, and a knot of tension in Killua's shoulders was released. He could still feel everything as though the hunt was just mere seconds ago: the thrill of the hunt in his veins, the sweet scent in the air, the warmth that burst over his fingers as the pumping heart laid crushed.

Killua took a shaky breath, and it was too loud in the silence. Too loud to an assassin's ears, too loud to a hitman's.

"Sleep tight, Killua," Reborn said, and there was no pity in his voice. Still the same derision that Killua was faced with when he first failed to assassin him. "Know that I'm watching you."

Illumi had obsidian eyes like Reborn too. He did not know why he found Reborn's comforting.

Under those watchful eyes, Killua relaxed and slept, with the knowledge that he wouldn't wake up to a friend dead under his own hands.

Xxx

It started like this.

Months sitting in front of a computer tracking down the world renown Strongest Hitman, weeks traveling to the tiny unmapped island out in the middle of nowhere, and merely ten second until defeat faced Killua with a barrel pointed between his eyes, before he had even gotten a chance to attempt at his target.

Then, a kid of his own age popped out of the house that he accosted his target near.

"Ah, hello! Are you a visitor? You're my age! We don't have many kids around here. Ne, let's be friends, okay?"

It all started with a whirlwind named Gon Freecss.

xxx

(In the mafia, they called him the Sky.)

(Killua found that adequate in the beginning. Two weeks in Gon's company led him to realize that no, Gon wasn't the Sky.)

(He was Killua's world.)

xxx

It really started the moment he stabbed his mother in the stomach.

"I'm leaving," Killua said, bored and inflectionless as he watched blood dripped out of the wound he left on his mother. She would heal soon enough. All Zoldyck's are inhumanly tough. Inhumanly inhuman.

"Oh, my boy is all grown up," she sniffled, blowing her nose in her handkerchief. She pressed a hand into her wound, winced at its depth, and smiled. "So strong. You'll grow into a fine assassin, Killua, the best the Zoldyck Family has yet to see."

"Move out of the way, Mother," Killua said, taking another step forward.

Mother clucked her tongue, annoyance overtaking the pride in her son. "Don't be rebellious, Killua! We're not letting you go. My boy, all alone out in the world?"

Killua flashed his hand warningly, nails sharp as blades and still dripping with blood.

"You're threatening me?" his mother gasped. "I'm your mother. Your mother!"

Killua tensed as the atmosphere around his mother grew darker. His mother was dangerous in her own right, he knew, and yet, he refused to back down.

The dark energy around his mother vanished as soon as it came, and then every instinct in his body was telling him to flee, except his muscles were all locked up.

"Anata!" his mother said, and there was his father, slowly ambling up behind Killua. "Quick, convince Killua not to go. Then, we'll also need to discipline him again."

Killua forced himself to turn around toward Silva. He bowed. "Father, I wish to leave this family. Please give me permission."

"Is there a reason why you want to leave? Even your eldest brother Illumi hadn't yet," Silva said. Killua snapped up in surprise; his request wasn't immediately rejected.

His mother's lips parted, looking like she wanted to protest against not immediately dragging Killua back to the dungeon for disciplining.

Silva held up a hand before she could speak.

His mother snapped her mouth shut.

Silva's eyes were still on Killua.

It felt like a test.

It felt like a chance.

"It's boring, being an assassin, killing day after day," Killua said honestly. He met his father's eyes. "I want more from life."

"You think you're going to find that by leaving home?" Silva asked. Behind him, Killua could hear his mother tearing and biting into her handkerchief, respect for her husband keeping her from interfering, but not from feeling agitated.

"Yes," Killua answered, without a second of hesitation or fear.

Silva stared at him for several seconds, then finally nodded. "Alright," he said, and hope soared in Killua.

His mother screeched. "Anata, you can't just let him go! He's our son!"

"Kikyo," Silva said, taking Mother's hand in his. "If he can injure you, then perhaps he really is ready for the world."

Mother sniffled. "But still…"

Silva nodded in agreement. "Still, we need proof." His father turned back to Killua and Killua straightened up. "Killua, if you really want to leave the Zoldyck Family, then prove yourself strong enough. I've recently received a request for a target. If you can complete it on your own within two years, we'll acknowledge that you're strong enough to survive it without us. If not, you'll come back of your free will, accept your mother's punishment, and not leave until you have her permission."

"Alright," Killua agreed easily. The logic was sound, and it wasn't like Killua hadn't completed many kills on his own before, albeit with Zoldyck's resources to locate his target.

"Anata?" his mother said, looking up at Silva. "The target you're speaking of…"

Silva nodded. "It's him."

"Oh," his mother said, and for the first time since Killua agreed to this, a sliver of uncertainty entered his mind. To reduce his mother to a single syllable like that, just who was his target? Another assassin? Don of a mafia family?

"Father," Killua started, "who…?"

Silva and his mother turned to look at him. A wide smile split across his mother's face. Gleefully, she told him, "The Sun Arcobaleno, Reborn." She practically giggled as she finished, "Also known as the Strongest Hitman in the World."

Xxx

Reborn, the Strongest Hitman in the World, was everything and nothing like Killua thought. His charge, a boy who was the same as Killua, was nothing he expected and everything that he wanted.

Gon was his friend.

He was also the heir to the Vongola Famiglia, the grandfather of the Mafia World. His father was supposed to be next-in-line after the death of all Nono's sons (plus one that was frozen, ineligible), but since he was too free-spirited (too keen, too smart, to be caught up in a scheme like that), he had spirited far away and disappeared from the surface of the earth the moment he heard about it. The only trace he left of himself was his son, according to Reborn.

"Not that he was around much at all before," Mito-san added bitterly, the smile that Killua had always seen on her face twisting to a frown edged with exasperation.

Killua didn't know when he went from trying to kill Reborn at every possible moment once Mito-san and Gon had their head turned around to simply hanging out with them and enjoying every moment of it. It was almost surreal, how happy Killua was on Whales Island. It was everything he wanted from life when he left his home.

Except he didn't leave, not really.

Not until he killed Reborn.

Xxx

So he went back to trying to kill Reborn, the moment Gon and Mito-san turned their back. He berated himself for ever being distracted enough by fun to even stop, despite knowing it was futile, so futile. Killua knew their strength was so far after that he might as well be an ant and Reborn, a god.

Still, he tried, because that was the only thing he could do.

Xxx

"Killua," Gon said one day, "why did you go back to trying to kill Reborn?"

Killua stared at him. Sometimes, when all he saw was the oblivious, childish side of Gon, he forgot that he was also made of up instincts and perceptiveness as well.

The Vongola Intuition, Killua's mind whispered at him.

Killua opened his mouth, a thousand and one lies ready to be used, and what came out was the truth. Gon sat down, frowned at him, and listened.

At the end of it, Gon's brows were furrowed so deeply that it looked like it was going to be a permanent fixture to his face. "I don't really understand," Gon said, tilting his head to the side with his arms crossed and eyes closed as he thought about what Killua told him. Even after Killua admitted he was an assassin, he was still so lax around him. "Your family let you go, right?" Killua nodded. Gon's eyelids parted and clear eyes met Killua's. "So why can't you just not go back when the time is up?"

Killua opened his mouth. Closed it. Opened it again.

His answer was… so Gon. Naïve, simple, yet perceptive. Why can't Killua just not go back? His family was going to send people after him, but he was strong enough to defend himself.

Himself.

He looked over at Gon and faltered. Could he protect Gon and Mito-san, in addition to himself?

'No,' Illumi uttered from the back of his head. 'You won't defend anyone. You're a selfish boy who only knows to protect himself. I know. After all, I'm your brother.'

"It seems like the Vongola Decimo has spoken." Killua jumped as a piece of the ceiling fan dropped down on them. The gray layer of the piece slipped off, before transforming back to its original form. Leon, Reborn's chameleon. He glanced over at Reborn, who smirked at him. Killua didn't sense him in the room at all. Did this mean that all the times when Killua was able to, Reborn wasn't using all his full ability to conceal himself? His pride bristled at that, especially at the smug look Reborn casted him. "Welcome to the Vongola Family, Killua."

"What?" Killua slipped out, startled, at the same time Gon cheered.

"Killua, we're in the same family now, aren't you happy?!" Gon threw himself at Killua and hugged him tightly. "You don't have to go back to your other family now!"

"Don't be ridiculous," Killua hissed, a little too harshly in face of the commotion and his own confusion. Gon withdrew from him with a half-wounded, half-confused expression. "Sorry," Killua said, looking away.

"Killua?" Gon said, and when he didn't reply, he looked towards Reborn. Killua clenched his hands into a fist and could feel his nails straining to grow longer for a kill. Reborn, the cause of all this indecision. Killua had finally found what he want in life, how he want to spend it and with whom, and yet, his ticket out of his old life happened to be Reborn, friend of Gon. Gon, who would never forgive him if he killed Reborn.

Not that you could, a derisive part of him mocked.

"Think, Zoldyck, think," Reborn said calmly, and Killua hated how he acted so above him, even though it was warranted and well-backed. It wasn't even the attitude that bothered him, however. It was the fact that he acted like a teacher.

Illumi's face flashed through his mind, and Killua felt sick.

"What harm is there in joining the Vongola Family?" Reborn asked.

"Mafia and assassins never mix, you know that!" Killua hissed. Reborn raised an eyebrow at him, before Gon interjected.

"Eh? Why not?" Gon looked at him, eyes wide and curious, and something in Killua broke. Shattered.

He laughed.

"Killua?" he said, shaking him when he didn't reply. "Ne, ne, Killua. Why are you laughing?"

Killua tried explaining, but he was shaking so hard that he couldn't. Was the answer really that simple? The chasm between mafia and assassin, was it really that easy to cross?

Perhaps, Killua conceded in his mind, it was. He glanced down at Gon and grinned. Gon, born and raised civilian Gon, who automatically grinned back, and Killua felt the same thing that was shattered in him remade. Maybe what he needed was just some outside perspective.

"Hey, Gon," Killua said, after casting an uncertain look at Reborn. "Can I really just join your family? Just like that?"

Gon laughed, the sound tinkling in the air. "Of course, Killua, you're my friend." He paused, before tilting his head to the side to gaze at him. "Besides, letting you join Vongola's going to help you, right?"

Killua nodded. Right. Not even the renowned assassin Zoldyck family was willing to go against the bigshot Vongola Family of the mafia.

He paused. Well, maybe. With the Zoldycks, anything was possible, but… Killua glanced over to Gon.

"I'll protect you," Killua promised Gon earnestly. Assassin hunt alone, but mafia as a Famiglia. His eyes slid to Reborn, and to the shadow of Illumi he always saw behind him. "I'll protect him."

Illumi the shadow gave him a disdainful look and vanished, but Reborn nodded with a satisfied smirk. So maybe, that was enough.