Note: This story is written in Killua's POV and takes place before he meets Gon. It's like a recollection of his memories and what happened. Hope you guys enjoy! Let me know how I'm doing and if you have any questions!
Flames aren't welcome, but constructive criticism is always good!
One last thing, don't forget to check out my other KilluaxOC fic. :D That one is an actual story rather than a oneshot.

Hunter x Hunter belongs to Yoshihiro Togashi.

.::The Reason for Leaving Home::.

From the day I was born, all my parents taught me...

...Was how to kill.

We were the Zaoldyecks, the monsters of Kukuruu Mountain, a family of assassins.

And I was chosen as their heir.

For a while, I didn't mind. I had the most fun whenever I did a job. It was like a game, except I knew I would never lose. "Never strike unless you're 100% sure you can make the kill." My dad would tell me. I never disobeyed him, didn't feel a need to. In the beginning, I thought I was suited for the job. I never thought I'd change my mind.

She was the reason I did.

I think I was 10 years old when I met her... or was I 9? Ah, who cares. That day, me and my brothers were having a meeting with my dad until my mom burst in. She pulled a little girl in by the hand and screamed about how she wasn't informed of the "situation." According to my mom, she was only paid to dispose of the parents, not the child. "The child" She said, "Would be extra work for no pay." The girl looked so tiny and fragile, I thought she'd break any minute. Her black hair was tied up in messy pigtails and her brown eyes were wide with so much fear I thought they'd pop out of their sockets. That would've been interesting to see.

I remember my dad glaring at my mom, asking why she brought her here. Back then I thought it was weird too, but now I know it was my mom's maternal instinct... and her twisted form of love. Maybe it was just fascination. I'll never forget the sight of her trying to hide behind my mother's dress as my dad got up and walked over to her. To this day I wonder why she wasn't scared of my mom.

At first, it seemed like dad didn't want the girl here, but later on, he asked for her name. Mom gave her a push forward so she stood in front of my dad. When she was too scared to say anything, my dad placed a hand on her head and smiled at her, saying we wouldn't hurt her. Tch. Yeah right.

Her name was Lucia. She was nine.

After asking about her, my dad stood up and asked one last question. "Do you want to stay here?"

The stupid girl said yes.

If you asked me to describe Lucia, I'd tell you; annoying. Annoying and stupid. In the beginning, I wanted nothing to do with her. After trying to befriend Kanaria, I decided it wasn't worth it. I was told many times by Illumi and my old man, "We live in a completely different world. Assassins have no need for friends."

Still, one thing was for sure. Lucia was different from everyone who lived here. Everyone here had a cold, serious air about them while Lucia's presence was warm and carefree...

Comforting...

She really was like a little girl. She acted so free even though she knew she was caged. Since my dad accepted her into our home, she would never be able to leave. Still... she kept smiling.

I hated it.

"You're an idiot, you know that?" I said to her. It was the second day she was there and I was sitting in my favorite tree, holding onto my skateboard while she was busy raking the leaves. Her hair was tied into a braided ponytail that day, thanks to mom.

"Huh? What do you mean?" She stopped raking and her big brown eyes stared into mine.

That was the first thing that surprised me about her. Unlike all the other servants, she never called me "Killua-sama" or "Master Killua." Maybe no one told her about the differences in our worlds...

Or maybe she really was just an idiot.

I leapt off the tree and landed in front of her. "Why didn't you say no? Now you're stuck here as a servant."

She looked away from me to the pile of leaves she gathered up. "I have no where else to go." I heard her take a breath and look up at the sky with another one of her smiles. "So I might as well try to be happy with what I have, right?" She turned to me with that same, bright, annoying smile. It surprised me, but I still wanted to cut it out.

Lucia was the only person in our estate who couldn't open the Testing Gate. She didn't need to, but because of that, my mom and dad assigned her to do the housework and other chores. Sometimes my mom would take her to the main house to dress her up. Aside from my grandpa and my dad, my mom was the only one in our family who liked her at the time. I think it was because there were no other girls in our family. Heh.

For the most part, things stayed the same, even after three months passed by. Get up, brush teeth, eat, train, eat more, skate, go to tree, eat even more, sleep. The only thing that kept changing was Lucia. Everyday after I skated and headed to my favorite tree, I'd see Lucia sitting by it, smiling at me; and everyday, I'd ignore her and climb onto my favorite tree branch. I never said anything to her and she never said anything to me. The silence wasn't uncomfortable, it was nice. But there was one day that silence was broken.

"Ne, Killua."

"Hm?" I was resting against the tree with my eyes closed.

"Why don't you ever laugh?"

She was weird. Completely and utterly weird. I didn't know how to respond at first, but eventually, I smirked and looked down at her. "Did you get hit in the head or something today, moron?"

My voice came out a lot harsher than I intended it to. I expected her to get upset, but she didn't. She started laughing, catching me completely by surprise. At that point I decided...

She was definitely abnormal.

"I got you to smile!" She grinned, pointing a finger up at me.

I felt my eyes widen a bit and quickly turned away from her. When I think about it, that's when things really started to change. She was the only one who treated me as an equal. There was no gap between us- no differences in status.

Since then, I'd help her out with the chores whenever I had free time and happened to be around. There was a day where she was taking out the trash and the bag was... bigger than she was. How she usually managed to handle it, I don't know.

"You're too slow." I grumbled, lifting the bag up with a hand. "Where does it go?"

"Ah!" Lucia made a move to grab the bag, but I moved it away from her. "Killua... you don't have to help me. I can do it myself."

I lifted an eyebrow at her and smirked. "And how many centuries will that take you?"

She pouted and folded her arms across her chest. I thought that was kinda cute. "I did it in 2 hours once!"

I laughed. Hard.

That was the first time I've ever truly laughed. I didn't know how... relieving it could be. I opened my eyes and stared into Lucia's shocked face, which made me laugh more. Pretty soon, she started laughing with me. It was kinda... nice to be able to laugh together with someone.

Pretty soon helping Lucia with chores became more fun than working. I was never... bored around her.

Her smile was her best feature. I hated it at first, but I grew to like it more and more. It was the only light in this hellhole.

I thought all that idiot could do was smile, but I learned that even the brightest light could go dim. It was about half a year in, and Lucia wasn't sitting by the tree waiting for me like she usually did. So that time, I waited for her. I waited until the stars came out and until I had to go home. When she still didn't show up, I snuck out of the main house and skated to the butler's quarters.

Her room was on the second floor, right by a tree. She left her window open, so I climbed up and leapt onto her windowsill. I knew something was wrong when I saw her curled up into a ball, leaning against the foot of her bed. I asked her where she was the entire day, and she told me she fell behind doing chores and was sorry for not being able to see me. She didn't look up to face me. I could tell from her voice she was crying, so I did the only thing I knew how to do. I knelt down by her... and hugged her.

Her body went stiff for a couple seconds, then she relaxed and cried on my shoulder. I think I was as surprised as she was, maybe even more, but I couldn't help it. Something about her crying bothered me and I wanted it to stop. Crying didn't suit her.

I don't know what happened to her. I never asked.

All I said to her was, "Don't cry Lucia." I wish I had asked, because now I'll never know.

A year passed by, and I started to like staying home, mainly because of Lucia. Everyday we would meet up by my favorite tree, and if she didn't show up, I'd sneak out of the main house at night to see her. Sometimes we'd just stay silent and watch the stars together, and other times we'd talk about what was happening around the estate. I made a habit of staying in her room until she got sleepy.

My parents weren't stupid. They knew I snuck out on several occasions to see her, and they weren't happy. I was severely punished the day after they brought it to my attention. Milluki carried out the whipping and electrocution, as usual.

"Be careful Killua." He said to me, smirking. "You never know who could end up hurt because of you." I glared at him. He must've felt my bloodlust, because he backed away pretty quickly. I was in solitary confinement for two days.

I never chose to be an assassin. What I really wanted was to choose my own future. I think I started thinking like that when I got closer to Lucia.

When I told my family after I was released, my mom burst out crying, screaming about how much potential I had. I sighed and shrugged my shoulders. None of that really mattered to me anymore. When they asked me why, I told them, "Work got boring." Simple as that. In order to appease my mom, I told them I'd stick with it for a while longer – just to see if I was really making the right decision.

After my dad dismissed me, I grabbed my skateboard and headed back to the tree where I hoped Lucia was waiting. Her blurry figure became clearer and clearer as I got closer, and I was finally able to make out her smile. It didn't last too long though.

"Killua! Are you okay?!" She ran over to me and stared at my legs and my face. She was worried. Ah man...

"I'm fine! Really." I smirked at her, giving her a thumbs up.

"Fine?! You look like a mess!" She reached her hand up to touch my cheek. If I was any average person, I would've flinched from the pain, but since I'd been going through this torture since birth, I had a high tolerance.

I sighed and stared into her big brown eyes. She looked like she was about to cry. "I'm used to it, idiot." I told her with a smirk, pushing her forehead with my finger.

Before I knew it, I felt her hand grab mine. "Even if you're used to it, it still hurts, doesn't it?" She asked, looking down at her shoes. When I didn't give her an answer, she squeezed my hand gently. "That's too sad." she whispered. My eyes softened and I followed her gaze to the ground, where I saw the damp areas where her tears fell.

"You're such a weirdo..." I mumbled, squeezing her hand gently back.

I don't remember how long we stayed together like that, but I remember how content I felt.

"You're getting too attached." Illumi said as I stepped through the doors of the main house. I ignored him and kept walking to my room, hearing him sigh behind me. If I had known what he was up to back then, I would've stayed and took his advice. The next morning, I left my room to come face to face with him again.

"What do you want?" I growled, annoyed by his suffocating presence. My brother always had a disturbing air about him.

"Kil. Lucia's looking after Mike today."

I lifted an eyebrow suspiciously, wondering why he told me. "She never looks after him."

"Mom decided on it." Illumi stated, walking away.

I couldn't help but feel uneasy about the whole thing... Then it occurred to me.

Lucia couldn't open the Testing Door.

How did they expect her to look after Mike if she couldn't do that?! The situation reeked of trouble.

I was out the door and running before any other thoughts could enter my mind. If Lucia walked out using the fake door and stepped back in, Mike would kill her. My heart was racing. I wasn't really sure why I was so panicked – why I cared so much about that girl in the first place.

My hunch was right on the dot. Mike was ready to turn Lucia into lunch. My body reacted faster than my thoughts, and before I knew what happened, Mike was in front of me, wagging his tail.

"Mike." I looked at him with a stone cold gaze. "You will not attack Lucia, ever again." Mike growled lightly at the command and walked calmly over to Lucia (who was on the ground frozen in terror) to sniff her. I ran over to her and pulled her to me, resting my chin on the top of her head. The panic I felt earlier began to ebb away.

I didn't need to apologize. She could tell I was sorry from the way I held her. I asked Lucia what happened – how I got Mike to stop – and she told me that I whistled for him before he could get her. I didn't remember any of it. It was probably the adrenaline.

But that day I realized how much danger I put her through. She was in danger because I let her get close to me. She wasn't safe anymore.

And it was my fault.

From that day on, I wanted to get stronger. I wanted to be strong enough to protect her... and her smile. Because of that, I decided to continue my training as an assassin. I can't believe how stupid I was.

There came the day my dad told me I was going to be sent away for a few weeks for training. By this time Lucia had been with us for three years. After I found out, I followed my usual routine and later on, headed to the tree where I was sure Lucia would be waiting. Whenever I left home for training, I always told her so she wouldn't worry.

She wasn't there.

I thought maybe it was because she fell behind doing her chores again, so I left and skated towards the butler's quarters. When I didn't find her in her room, I went looking for her until nightfall. I still couldn't find her. I even asked Gotoh if he knew where she was, but he shook his head. "I'm sorry Master Killua. I do not know of Lucia's whereabouts at the time being." So instead, I told him to tell her where I was going. I was leaving the next morning, so I had to head back to the main house...

Without seeing Lucia.

I was gone for three weeks. Usually I didn't mind being away for that long, but I had this annoying, nagging feeling with me ever since I left. I didn't know why, since I normally enjoyed being away from home.

When I returned, I felt myself dash off to the direction of the tree. It was strange, like my body was moving all on it's own. I thought of myself as a magnet.

Lucia still wasn't there, and it was midafternoon. I felt something heavy in my chest, but I didn't know what it was.

"Dammit." I heard myself hiss. "Where is she?!"

"Killua dear!" I heard my mom's shrill voice call. There was something about it that really pissed me off. I knew.

"Where's Lucia?" I tried hard to keep my voice calm.

"Let's go Kil, your father is wait–"

"Where's Lucia?" I repeated.

"Three weeks of being away from home and you ask where she is?" My mom's calm demeanor instantly changed. "KILLUA! IT WAS FOR YOUR SAKE!"

From my mom's reaction, I knew Lucia was somewhere in the main house. I never fully understood the relationship between her and Lucia. I thought she liked her, but I'm guessing she started to hate her when she found out about our friendship.

I made a step towards the main house and felt her hand grip onto my shoulder, pulling me back. "KIL! LISTEN TO ME! I'M YOUR MOTHER!"

She was getting really annoying, so I looked over my shoulder and glared at her. "Don't touch me."

That was more than enough to get her to leave me alone.

I found Lucia locked up in the basement of the main house. I don't know how long she was there, or what they did to her, but I haven't seen her that scared since the time we first met.

"K-Killua...!" Her voice came out in a raspy stutter.

I ran to her, reaching out to grab her outstretched hand from between the bars. "I'll get you out of here." I whispered, grabbing onto one of the bars with my other hand.

"No!" Lucia lunged forward and grabbed onto my arm, stopping me from breaking the bars. "If I'm gone, then you'll get in trouble."

She never ceased to amaze me.

"AHO!" I yelled, brushing her hand off. "I can't just leave you here!"

"Actually, her time is up." I turned around and saw my grandfather at the top of the steps, staring down at us. "You can take her, Killua." Huh. Gramps was always the nice one in the family.

After that whole mishap, I walked Lucia back to the butler's quarters, up to her room, and sat down by her in silence. I knew I couldn't protect her from my family. The only option would be to run away, and that was when I made my decision.

I was going to leave home, and I would take Lucia with me.

"Lucia." I turned to her slowly. "I'm leaving this place." She opened her mouth to protest, but I cut her off. "I want you to come with me."

"But..." She looked down at the carpet and shuffled her feet. "Wouldn't you get in trouble...?"

She was more worried about me than she was for her own safety... the idiot.

"I can't..." My fists tightened around the bedsheets beneath me. "Protect you..." I looked away from her and to the ground. "Like this..." I stared up at her, hoping she would understand.

I saw her eyes widen for a bit, but then she looked up at me and smiled, placing her hand on top of mine. I didn't even realize I was shaking.

"Okay..." She whispered. "When do we go?" The sound of her voice was calming... It put my nerves to rest almost instantly.

"I'll be here tomorrow night at 1am." I stood up and rested my hand on the windowsill. "Be ready to leave by then."

I was about to jump out the window when I felt her arms wrap around my torso. I paused for a minute, feeling my body stiffen, then I placed my hand on top of hers, giving her a gentle squeeze before I leapt out and ran off into the darkness. I didn't want to look back.

When the next night came, I grabbed my skateboard from the storage room and crept out of the main house. My heart was pounding from the adrenaline rush. I guess I was a little scared, but I had to do it... To protect her.

And not only that, but I was getting tired of killing anyways... it was annoying. I wanted my own future. A future free from killing, a future filled with fun, a future I hoped Lucia could be a part of.

All those hopes came tumbling down the moment I hopped through her window.

It was a shadow. A tall, lean shadow that resembled that of my brother's. My eyes widened and I felt my heart thump wildly against my chest. So fast I could hear it echo in my ears. The shadow's back was turned to me, then it slowly whirled around, causing my heart to beat even faster.

Then I felt like my heart stopped. I could feel cold sweat run down from my forehead to my neck. My body shook. I couldn't find the strength to speak.

"I-Illum-" My voice came out in a weak stutter. I wanted to know why he was there.

Illumi turned to me with those dark, emotionless eyes, then looked down to the ground next to him. I forgot how to breathe. My eyes slowly followed his gaze onto the bloody bundle on the ground.

It was Lucia.

"Mom's orders." He said simply, walking right past me. "It was your fault, Kil. You shouldn't have let her get so close."

My hands clenched into fists as my body shook. I couldn't tell if it was from the fear or the sorrow.

"BASTARD!" I snarled, flexing my hands to elongate my nails. I wanted to rip his head off.

...But when he turned around and stared at me with those eyes... I knew I couldn't do it.

"You can't kill me, can you Kil?" The calmness of his voice pissed me off. When I didn't make any motion to run after him, he turned his back to me and placed his foot on the windowsill. "I thought so." He said, leaping out the window.

I quickly turned and ran to Lucia, scooping her up into my arms and holding her close to me. "Lucia...!" She was bleeding from the pins lodged into her back, but she was still alive. I wanted to pull them out of her body, but I didn't want to make her condition any worse.

I grabbed onto her hand and stared into her eyes. She was getting colder by the minute and her eyes were starting to lose their brightness. "Y-You're going to be okay!" I shouted. I didn't know whether I was trying to convince her or myself. "Don't die! You can't die, you idiot!"

"Killua..." Her voice was barely a whisper. She looked up at me and shakily lifted up her arm, placing her cold hand against my cheek. I didn't realize I was crying until I felt her thumb wipe away the tears. "Don't... make that face..." A small smile slowly made its way onto her face.

"You..." I was at a loss for what to say. "How can you smile when you're-"

"You should..." She took in a deep, ragged breath. "Make happy memories... outside..." She breathed out slowly. "Sorry I couldn't... come with you..."

"Don't be stupid!" I shouted, pulling her body closer to me. "We'll see the outside world together...!" I heard my voice crack a bit.

"Thank you... for always watching... over me..." Lucia's smile never wavered. I could see tears forming on the edges of her eyes. "Ne... Killua..." Her hand started to fall from my face, but I held it in place with mine.

"I never told you..." Her eyes slowly closed and her smile began to fade. "That I..."

"...Lucia?" My body began to swirl into a panic as I gently shook her. "Hey... Lucia..." She didn't budge.

At first I thought it was my mind playing tricks on me. Maybe she was just tired and needed to take a breath before she could finish. She probably fell asleep. If I shook her enough she'd wake up and smile at me again. That's what I hoped...

But when I started to shake her more and more, I realized that she would never be able to finish her sentence.

...And I don't think I've ever cried that hard in my life.

The bitterness I felt towards Illumi and the rest of my family was beyond hate. If they thought taking Lucia away from me was going to stop me from running away... they thought wrong.

"Make happy memories outside."

That was Lucia's final wish for me. I'd be stupid if I couldn't grant her this one, little thing.

So I waited.

I waited until the day came Illumi had to leave for a job, then I ran, beating Milluki and mom up in the process. I don't regret what I did. I don't think I ever will.

It was more than just boredom. The reason I left home – The real reason why, was because of her.

Lucia.