Full Summary:

The Hunter Exam was supposed to be a way to keep an eye on Killua, to make sure he stayed safe and to keep Illumi away from him for as long as possible. Passing the exam and receiving her Hunter License was just an added bonus, something that could prove useful for future jobs. She was to be her younger brother's shadow- his protector. What wasn't supposed to happen was for his new friends to become hers as well, particularly the blond Kurta survivor. Assassins weren't supposed to have hearts. That had been drilled into her since birth.

So why was she so willing to break that rule for these people?

Disclaimer: I do not own Hunter x Hunter. All I own are my OCs and original ideas.

Prologue

Killua couldn't breathe.

Not literally, of course. While he had been running non-stop from the house and was nearly at the front gate, his breathing was as calm than if he had been on a leisurely stroll. His stamina ensured that he could run for miles without breaking a sweat.

No- he couldn't breathe figuratively.

Because he was escaping from home. Had just stabbed his mother and Milluki. Was defying his father in the greatest way possible. And was getting away with it, though he knew it was only because his father and Illumi were away on missions. If either of them were home right now, Killua would never have even made it out the front door. So when the gate entered his field of vision, something loosened in his chest.

Almost there.

He was almost there. Just a few more steps, and he would be free. Free from his family, free from the rules and structure, free from killing. Free to be a kid for the first time in his life. Only ten steps separated him from that freedom when, from the pocket of darkness between the trees, a figure emerged and stepped with feet that made no sound onto the path in front of him. The sudden appearance had him skidding to an abrupt halt and immediately put him on edge.

Shit. Killua cursed himself silently as the figure removed the hood shielding their face. His stomach turned uneasily as he berated himself for making such an obvious mistake. In the rush of getting away, it had completely slipped his mind that another member of the family was returning today from a job.

Illuru.

His older sister stared at him with her usual lack of expression, but the slight tilt of her head told him of her curiosity.

"You're leaving," she stated softly. Her voice was free of any emotion, giving him no indication as to if she was upset about it or not.

"That's right," he said, lifting his chin defiantly, hoping to hide how anxious he was. Anxious, because as always, he had no idea what his sister would do. If it were a few years ago, she would grab his hand and run out the gate right along with him. But so much had changed since then, and she was no longer that person. Now, she was the perfect example of a Zoldyck assassin. Calm, composed, efficient, and obedient. And although his father was not here to give orders, they both knew what they would be.

Do not let Killua leave.

There was no chance of evading her, as she was the master of evasion, and fighting her was out of the question. That left talking to her, appealing to the sister that had once risked and received severe punishment for sneaking him out of the house over and over again, who had always managed to extend their time for a job just to give him a day to himself, to recover, to have fun. His lips parted, ready to manipulate himself out the situation, when Illuru's voice cut in quietly.

"What will you do?"

"Huh?" he blinked dumbly, once again thrown off by her.

Her head tilted a fraction further, the movement so miniscule it didn't even shift her hair, but his eyes caught it.

"What will you do?" she repeated, "When you leave?"

When he leaves?

Hope stirred in his chest, and he couldn't stop the smirk that pulled at his mouth.

"I'm going to take the Hunter Exam. I'll pass with no problem, but it should be somewhat entertaining at least."

Depthless eyes stared at him for a long minute before she let out a soft hum and closed the space between them. He tensed, wondering if he had made another mistake, when her hand fell onto his head and lightly ruffled his hair.

"I don't doubt that you will." She retracted her hand and moved past him without a sound. "I've held you up for too long, but I'll distract mother. So there's no need to worry about that."

His wide eyes stared at her retreating back for a moment before shaking off his surprise and nodding, not that she could see it. He turned as well and had just placed his hands on the gate when her voice had him looking over his shoulder.

"And Killua?" She turned her head, empty black eyes locking onto questioning blue ones. "Be careful... and have fun."

Killua grinned impishly, happy to have his sister back if only for a moment, and nodded.

"You got it, Rue." The nickname slipped off his tongue without thought, and he turned back to the gate, pushing his way through. And if he had turned a second later, he would have seen the way Illuru's impassive face slipped ever so slightly at the sound of the name he hadn't used in years. Would have seen the near unnoticeable pain that flashed through her eyes before disappearing.

But he didn't. And within moments, he was gone.

Hysterical sobs and screams met Illuru as she stepped through the threshold of the house and wound her way around upturned furniture to the sitting room. She paused in the doorway and leaned her shoulder against the hard wood, content to take in the scene before her. Killua had caused quite a mess it seemed.

Blood stains on the carpet and wall. Milluki, white faced and trembling with rage, standing to the side as a butler stitched a wound on his leg. And Gotoh, hands raised in a placating gesture directed at the inconsolable woman before him.

"Look at what he's done!" their mother screeched, hands fluttering around her cut face. Tears streamed from under her visor relentlessly, mixing with the blood and pooling around the creases of her mouth which were pulled up into a grin, making for a truly grotesque sight. "He was so cruel, Gotoh! It makes my heart melt just thinking about it..." Her lips quivered and fell into a frown. "But to leave home... to leave us... oh, he'll be putting himself in so much danger..."

As their mother continued to fret, Illuru felt the air shift beside her.

"Just arrive home?" she murmured.

"Yes," Illumi replied, casting his eyes around the room before settling them on her. "As have you."

She nodded her head, ignoring his inquiring stare.

"Killua ran away." Though it was posed as a question, she heard the clear statement in it.

"It would seem so," she agreed quietly.

Unblinking eyes never left her face. "And you didn't see him leave?"

You got it, Rue.

"I'm afraid I arrived shortly after it happened."

"Is that so?" There was no suspicion in his voice. No anger. Just a touch of curiosity that she knew better than to believe.

Finally looking away from their mother, Illuru turned her gaze to Illumi.

Rue.

"Yes."

Silence stretched between them for several minutes, their mother's muttering and Milluki's shouts fading to the background as black eyes remained locked onto each other- two sides of the same coin.

Illumi was the first to look away. "That's unfortunate."

"It is," she said, an unseen tension leaving her though her face betrayed no such feelings.

They both knew that she was lying, of course. She could make anyone believe her words, but not Illumi- never Illumi. They could see through each other's lies in a way that only twins could. So when they did lie to one another, it was not out of the need to deceive the other, but out of principle. While Illumi knew she was lying about it, she could not, in good conscience, tell him that she saw and allowed Killua to leave. She would not betray her little brother in that way.

"Illumi!" their mother cried, finally taking notice of his arrival. If she saw Illuru next to him, she said nothing of it.

"Mother," he greeted. He shifted his weight to the side, arm brushing against hers, but made no move to leave. And while their mother surely noticed the silent gesture, she once again ignored it, keeping her focus trained solely on her son.

Illuru cast her eyes to the side, wanting nothing more than to sink into the inky darkness of the shadows and leave this mess behind for Illumi to clean up. And perhaps she would have had it not been for that one word.

Rue.

Her heart constricted at the memory. Killua had not called her by that nickname in four years. Had not looked at her with that light in his eyes since the day of their last mission together. And that was why she stayed. Even though she knew it was wrong, even though she could feel the phantom sting of the whip on her back, could hear the echo of her father's voice- it all became a distant thought.

Rue.

"You are to follow him and keep an eye on him. And when the time is right, bring him home."

At their mother's words, Illuru's eyes snapped up, yet she kept them carefully blank as her mind spun.

She doesn't want him brought back immediately?

She had assumed that their mother would want Killua returned as soon as possible. That she would not want him outside the walls of their home for any longer than absolutely necessary. She had been prepared to keep that from happening, to give Killua as much time as she could to get away. She had not taken into account that she would want him followed instead. And by Illumi no less. But if that was the case, then she would simply adjust accordingly.

Illumi nodded once. "I require a Hunter License myself, so I will have him home by the end of the Exam."

Their mother let out a deep breath and slumped onto the floor. Gotoh, seeing the fight finally leave her body, set to work on patching up her wounds. Illumi took it as his cue to leave, and Illuru followed silently behind as they made their way through the halls and up the stairs. Only when they entered his room did she finally speak.

"You'll be entering the Exam in a disguise, I assume?"

"Yes," he answered, voice slightly muffled from his place in the closet, "It would do no good to let Kil know I am there from the beginning. It would only scare him off. I won't make myself known until I have acquired my license."

She leaned into the wall behind her and frowned lightly in thought.

By the time Illumi gathered everything he needed from the closet and made his way toward her and the door, she had her plan set and her usual mask back in place.

"Good luck," she said out of habit.

"Don't cause any trouble while I'm gone," he responded lightly, breezing past her and out of the room.

She waited until she could no longer sense his presence before humming softly. "You know I've never been very good at that, brother."

With no time to spare, she strode a few feet down the hall and entered her own room, grabbing a few more weapons and other essentials, before slipping down the stairs and out of the house without a whisper.

It was a good thing she had no jobs lined up at the moment. For she had a Hunter Exam to attend.

Author's Note

Should I be starting a new story when I have other one's to focus on? No, no I should not. But here I am anyway! This last month or two, I binged my way through HxH and fell head over heals in love with it. So much so, that I had to create an OC for it, and oh boy, do I love her. Illuru is such a fun, interesting character for me to write, and the Zoldyck family has such a unique dynamic that I'm so excited to explore!

If you like this prologue or find it intriguing, don't be afraid to hit that follow or favorite button!

Reviews also make my day!

Until next time:)

~Dreamer