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The Phantom Assassin

Summary:

Kamishiro Rui is a seasoned assassin, unafraid to spill blood and get the job done. He assumes his assignment to kill the Phantom Thief will be no different--until he finds out his target is someone who was once very dear to him.

Notes:

this fic is loosely based on the trained versions of this mizuki card and this rui card

idc if rui is a detective in that card--he's an assassin now because i said so

(See the end of the work for more notes.)

Work Text:

Kamishiro Rui crept through the shadowy mansion, his footsteps silenced by years of experience. He was in the main sitting room now where the only light came from the moon shining through the towering windows. It was eerily quiet. Rui looked around the room, eying the crooked paintings and the furniture that lay tipped over on the floor. He slipped into the nearest corridor and prayed that the Phantom Thief hadn’t eluded him once more. Rui hadn’t actually ever seen the thief–no one had–but he was determined to find them. He’d never failed a mission and he didn’t plan on starting now.

Rui stiffened as he continued down the corridor and began to hear the faint crackle of a fire. His pistol was already cocked and loaded, but he tightened his grip on it as he turned the corner, hugging the wall. His eyes narrowed as he spotted the room where the crackling was coming from. The door was open, but Rui was leaning on the wall next to it so that anyone inside wouldn’t see him. The doorway glowed with warmth and the fire inside cast long shadows across the floor in front of Rui, but he felt a coldness emanating from the room that chilled him to the bone. He inched closer, clinging to the wall and holding his gun up by his head, ready to strike.

From where he was standing, Rui couldn’t see where his target was and he knew he would have to react quickly as soon as he stepped out of the shadows. The Phantom Thief was unpredictable–a fearsome, evasive force that wreaked havoc on the kingdom. Rui had no way of knowing what he would face when he entered the room that the thief was supposedly inside. He took a deep breath and stepped silently in front of the doorway with his pistol raised, rapidly surveying the interior of the room. It seemed to be some sort of study, with bookshelves lining the walls and a large desk sitting in the corner. Rui didn’t immediately locate his target, for they were sitting in an armchair facing away from him, towards the fire. He crept further into the room, relishing in his luck that the Phantom Thief happened to have their back turned and hadn’t seen him come in. Rui was close enough to see that the thief was reading a book when they suddenly spoke.

“Took you long enough,” the thief said, sounding bored as they flipped a page in their book. Rui froze in his tracks at the sound of their voice. It was shocking enough that Rui’s target had somehow sensed his presence, but what truly frightened him was the familiarity of the voice. He hoped desperately that he was wrong. He hoped that it was somebody, anybody else in that armchair, but if there was anyone in this world whose voice Rui would never forget, it was hers.

“...Mizuki?”

“Ding ding ding!” the Phantom Thief exclaimed in delight, snapping their book shut and hopping out of the armchair to face Rui. Mizuki certainly lived up to her alias, clad in a masquerade mask and a wicked grin. They looked Rui up and down, eyebrows raising as their gaze landed on his raised pistol.

“My, Rui, I sure am glad you were never the trigger-happy type,” Mizuki mused, eyes wandering from the gun to Rui’s face.

You’re the Phantom Thief,” Rui sputtered, still in disbelief.

“In the flesh.”

Rui simply stood there with his pistol still trained on Mizuki, not knowing what to do or say. He had certainly spilled more than his fair share of blood, but he paled at the thought of killing Mizuki.

“Are you going to shoot me, Rui?” Mizuki asked, sounding almost amused. It was like she was sure of the answer and just wanted to see Rui squirm. Rui still didn’t lower his gun, but his composure was cracking and his hand was starting to shake.

“You’re Japan’s most wanted criminal.”

“Well, yes,” Mizuki agreed, “but I sure hope you of all people aren’t going to give me a lecture on morality.” Rui’s eye twitched at that, but he still didn’t back down.

“You have a fifty million yen bounty on your head.”

“Are we just stating facts now?” Mizuki asked dryly, reaching up to remove their mask. “Of course people would pay to get their hands on this face.”

Rui’s breath hitched as Mizuki removed their mask and revealed the rest of their face. The past few years had been exceedingly kind to her; she had grown into her features, her eyes no longer big and childlike, but still full of mischief and as beautiful as the sky at dawn. Rui took notice of their hair as well, which had grown significantly since the last time he had seen it and now framed their face beautifully. She was breathtaking.

“Put the gun down already, Rui,” Mizuki said, crossing their arms impatiently. They stepped closer to Rui, stopping right in front of the barrel of the gun and daring him to shoot. “I know you don’t have the guts to kill me.”

Rui still didn’t move. He didn’t think it wise to let his guard down around Japan’s most elusive criminal, regardless of their history. He was stuck between two very unappealing options: make an enemy of his mentor for failing to complete a mission of this caliber, or kill the one person still in this world whom he had ever truly cared for.

“Ah, you really don’t trust me,” Mizuki said, glancing back at Rui’s loaded gun. “Well, I suppose I can’t blame you. It’s the first time we’ve seen each other in… three years? And now I’m the big, scary Phantom Thief. Gotta be a shocker.”

“You’ve certainly been busy.”

“You can talk, Mr. Big Shot Assassin,” Mizuki retorted, her eyes twinkling with amusement, “Seventy-eight jobs completed. Impressive.”

“You’ve been keeping tabs on me?” Rui asked, his eyes narrowing.

“Of course.”

“So you knew I was coming?”

“Obviously,” Mizuki said with a scoff, “I allowed you to find me. Did you really not find it odd how easily you tracked down the world’s most mysterious criminal, whose face has never even been seen? You’re good, Rui, but not that good.”

“But why?” Rui asked desperately. He couldn’t believe Mizuki’s cruelty, putting him in this position. And it seemed like she was enjoying it, too.

“Because,” Mizuki answered brightly, “I missed my… I missed you.” They met Rui’s gaze again, their eyes shining earnestly.

“You… missed me,” Rui echoed, feeling an unbelievably convoluted assortment of emotions as he took that in. Under different circumstances, perhaps he would’ve been overwhelmed by joy, but Mizuki had gone about missing him in an extremely frustrating way.

“You missed me,” Rui repeated, “So you led me to your location when I’m on a mission to kill you?” He was seething now, infuriated by Mizuki’s lack of consideration.

“Well, I know you would never kill me.”

“I had no idea you were the Phantom Thief! What if you hadn’t revealed your identity before I saw you and I shot you before I realized who you were?”

“I don’t know if you noticed, but I thought that one through,” Mizuki said dismissively. “Why do you think I sat where you wouldn’t be able to see me?”

“How do you know I still won’t kill you? I don’t think I even know who you are anymore.”

“You’ve always been sentimental,” Mizuki replied, staring at Rui knowingly. “Tick, tock, make a decision.”

Rui’s grip tightened on his pistol, his hand shaking more than ever. He gritted his teeth and glared at Mizuki for a few seconds before he finally exhaled and lowered his gun.

“See? I knew you’d make the right choice,” Mizuki said, the slightest bit of relief leaking through her confident facade. “Now, down to business.”

Mizuki moved back to their armchair and sat down, gesturing for Rui to take the one next to it. Rui reluctantly obliged, curious to know what Mizuki wanted to speak with him about.

“I have a proposition for you.”

“Do you now?” Rui asked, not liking where this was going but humoring Mizuki anyway.

“Work for me.”

Rui struggled to stifle a laugh at that.

“Work for you?” Rui repeated incredulously, “I was under the impression that the Phantom Thief works alone.”

“Up until now, yes,” Mizuki agreed, “but I’m starting to have goals I can’t achieve on my own. You’d make a good thief with your stealth training. Plus, if I ever needed someone killed, I could have you on my side. I’m an exceptional thief, but I’ve never been able to bring myself to kill.”

“Don’t make me laugh,” Rui said, scoffing, “You’ve pulled off heists single-handedly that even entire criminal organizations could only dream of. What could you possibly want to do that requires my help? There must be another reason.”

“Wow, Rui, I didn’t know you thought so highly of me–”

“Mizuki.”

“Fine,” Mizuki said, defeated by her failure to change the subject. “I’m… lonely. Like I said, I miss you, or whatever.” She looked away in embarrassment, clearly not accustomed to this level of vulnerability.

Rui’s eyes softened as he listened to Mizuki admit her feelings once more, no longer feeling as angry at her as he was the first time.

“Goodness, the great Phantom Thief has emotions.”

“Shut up,” Mizuki said with a pathetic attempt at anger, pink dusting their face in response to Rui’s teasing. “So what’s your answer?”

“I don’t know, Mizuki,” Rui replied apprehensively, “I still don’t really trust you.”

“Oh, come on, Rui,” Mizuki pleaded, “We were inseparable during our training. Do you really think that much has changed just because we took slightly different paths?”

“Slightly different? You’re the Phantom Thief. Who knows what you’re capable of?” Rui wondered aloud, looking at Mizuki with a mixture of fascination and fear. “You’re dangerous, Mizuki.”

“Says the assassin.”

“You had all the same assassin training that I had, yet you’ve done even greater things,” Rui said, his eyes full of cautious admiration. “Despite your apparent aversion to killing, I know you’re every bit as capable of slitting my throat and walking out of here as I am of shooting you. Don’t think I didn’t see that dagger strapped to your thigh.”

Mizuki simply raised her eyebrows in response, clearly having forgotten that she had met her match long before becoming the Phantom Thief. 

“Although, I must say,” Rui added, “you’ve put me in quite the predicament. How do you think Ozaki-san is going to react if I return and tell him I didn’t kill you?”

“Not well, I’d imagine,” Mizuki replied knowingly, crossing their legs and smirking. “I guess you don’t have much of a choice, huh?”

“Well, I could still kill you,” Rui said casually, fighting the urge to vomit at the thought. “After all, Ozaki-san has given me a home and a purpose, while you ran away and left me to fend for myself. Why should I leave him and gamble on you?”

“My, Rui, don’t you remember why you had to become an assassin in the first place?” Mizuki asked, eying Rui with the slightest bit of concern.

“What? Of course I remember,” Rui snapped. “How could I ever forget? It was my only way to survive.”

“And why was that?”

“What is the point of this?” Rui exclaimed, anger bubbling in his stomach at Mizuki’s insistence on dredging up his worst memories.

“Just answer the question.”

“My parents were killed,” Rui said coldly, “Why does that matter?”

“Who killed them?”

“What?”

“Who killed them?” Mizuki asked again, their expression unreadable.

“I-I don’t know,” Rui sputtered, “They were mugged.”

“Are you sure?”

“I… Of course I’m sure,” Rui answered, sounding ironically uncertain.

“Who told you that?”

Rui fell silent, suddenly realizing what Mizuki was getting at, but not willing to accept it.

“Rui,” Mizuki said gently, pushing him to answer the question.

“Ozaki-san,” Rui finally murmured, staring at the fire crackling in front of him. At first, Rui couldn’t believe that Ozaki was his parents’ killer. As he thought about it more, however, he couldn’t believe he hadn’t realized it sooner. Ozaki was like a father to him, yes, but he was also a seasoned assassin. He had taken Rui in at the age of twelve after the death of his parents and had been training him to take over his organization ever since. Rui’s parents had been nobles, so it wasn’t at all inconceivable that someone would hire Ozaki to kill them and steal their wealth.

“I’m so sorry, Rui,” Mizuki said quietly, grabbing his hand gently, “I thought you knew.”

“How long have you known?” Rui asked after being jolted out of his thoughts by Mizuki’s touch.

“I only figured it out after I ran away from home,” Mizuki explained, rubbing the back of Rui’s hand with her thumb softly. “I was… thinking about you a lot after I left and I started wondering how you ended up in that wretched life in the first place. I was born into it, my parents being who they are, but you… You were plucked from your life and forced to adapt to survive. Whenever I get my hands on Ozaki…”

Mizuki looked absolutely livid. Rui watched as the light from the fire flickered across their face, illuminating the features sharpened by rage. Rui, touched by Mizuki’s anger on his behalf, squeezed her hand.

“You… thought about me after you left?”

“Of course I did,” Mizuki said, sounding appalled that Rui would think otherwise. “Every day.” Their overly confident, quippy exterior had completely fallen away now, leaving only their most sincere and vulnerable self. Rui could see now that she was still the same person he had loved years ago. She was not the Phantom Thief; she was simply Mizuki.

Still holding their hand, Rui leaned slightly out of his armchair and closer to Mizuki. Mizuki followed suit, shrinking the gap between them to only a few inches. They nearly drowned in each other’s eyes trying to think of how to communicate all that had gone unsaid over the past few years.

“I missed you,” Rui said softly, saying all that needed to be said in three words.

“Oh, shut up,” Mizuki said as she reached out to grab Rui’s head with her free hand, pulling him in and crashing their mouths together. Rui’s eyes fluttered closed as his lips collided with the soft sweetness of Mizuki’s. He reached up to tangle a hand in her hair, still clinging to her hand with his other one. The kiss filled Rui with warmth, thawing the years of loneliness that had weighed him down in Mizuki’s absence. He never wanted it to end, but Mizuki eventually broke away and both of them were left gasping for air.

Mizuki regained their composure first, grinning proudly at Rui’s flushed face. She was glowing with confidence again as if delighted by the fact that she was able to fluster the stone-cold assassin who sat in front of her. Mizuki got up from their armchair and dragged Rui with them. The two stood in front of the fire facing each other, their fingers still intertwined. Mizuki looked up at Rui, placing their free hand on his shoulder.

“So, is it safe to say you’ll take me up on my offer?” Mizuki asked with a cheeky grin. Rui snapped out of his stupor and grinned back, already feeling happier than he had in years.

“Oh? What makes you so sure?”

Mizuki burst into laughter at that, clearly finding Rui’s teasing hilarious. Rui grinned even wider; he had missed that sound dearly.

“If I do accept your offer,” Rui said, reaching out to tuck a lock of Mizuki’s hair behind her ear, “do I get to kiss you more often?”

Mizuki’s eyes widened in surprise, but then they smiled playfully and said, “I suppose that could be arranged.”

Rui smirked in response and was about to lean down to kiss Mizuki again when the hairs on the back of his neck suddenly stood up.

Rui whipped his head to the right immediately, his eyes widening in shock as he realized Ozaki was standing in the doorway with his gun pointed at Mizuki. Rui reacted with lightning speed, ripping his pistol out of its holster and shooting Ozaki in the leg, but he was a fraction of a second too late. Ozaki fired just as the bullet hit him. The shot to his leg caused him to fall and miss his initial target of Mizuki’s head, but his bullet lodged itself in her chest instead.

Mizuki collapsed immediately, falling backward onto the floor in front of the fireplace. Rui whipped around again, dropping to his knees next to Mizuki. He gently picked up their head, cradling it with one hand and covering their wound with the other, attempting to staunch the blood rapidly seeping out of their chest. She was still conscious, but her eyes were fluttering and struggling to focus on Rui’s face.

“Rui,” Mizuki said weakly, “you didn’t… answer my question.”

“What question, Mizuki?” Rui asked, his eyes stinging.

“Will you… work for me?”

Rui couldn’t help but chuckle at that, despite the gravity of the situation. Mizuki always did have a way of making him laugh under even the most solemn of circumstances.

“Of course I’ll work for you,” Rui said softly, “but you have to live, okay? We still have to run away together.” Mizuki simply nodded weakly, their breathing becoming more labored.

“Think of all the adventures we’ll go on together Mizuki,” Rui said, his voice starting to shake, “The Phantom Thief and the Phantom Assassin. How about that?”

“That would be… nice,” Mizuki whispered so quietly that Rui barely heard it. Rui’s eyes were swimming in tears now, but he did not allow them to fall.

“Just hold on,” Rui pleaded, but he knew it was no use. Mizuki had lost too much blood. Her eyes were no longer fluttering; they were simply closed. Rui stopped feeling the faint rise and fall of her chest under his hand.

A single tear rolled down Rui’s cheek as he realized that Mizuki was gone. He didn’t scream or cry, he just leaned down and planted a single kiss on their forehead. He was saving his explosion of grieving rage for the man who lay bleeding in the doorway.

Rui stood up and grabbed his pistol again, walking slowly towards the door. His steps were calm; a controlled fury burned through him. He stopped when he was standing over Ozaki, looking down at him as he grunted in pain and blood pooled around his leg. Rui aimed his gun at Ozaki’s head. It took everything in him to not shoot the man right then and there, but he was determined to get some answers before he did.

“Why did you come?” Rui demanded, his voice sharp as a knife. Ozaki scoffed, seemingly amused by the venom in Rui’s tone.

“I couldn’t trust you with such an important job,” Ozaki said coolly, “so I followed you. I’m glad I did since you were about to run away into the damn sunset with your target.”

Rui nearly started shaking with rage at Ozaki’s words. He could barely even stand to look at him knowing that he was now responsible for the deaths of three of his loved ones. He couldn’t believe he’d been raised by this man for the last five years.

“You killed my parents,” Rui spat.

“Finally figured that one out?” Ozaki taunted, “I guess that bitch told you.”

“Yes,” Rui replied, swallowing his anger at Ozaki’s insult towards Mizuki, “and now you’ve killed her, too.” Just when Rui thought he’d gotten Mizuki back, Ozaki ripped them away from him.

“I do what I need to do to get the job done, kid. You know that.”

“And that’ll be the last job you ever complete,” Rui snapped, cocking his gun. “Goodbye, Ozaki-san.” Rui shot Ozaki right in the forehead, killing him instantly. It was his seventy-ninth kill, and he hoped it would be his last. He was done. If being an assassin meant that he’d someday end up like the man lying dead on the ground in front of him, Rui knew he couldn’t bring himself to continue doing it.

Rui set his gun down on the ground next to Ozaki’s corpse; he couldn’t bear to hold it any longer. He went back to where Mizuki lay, smiling sadly at the sight. Even in death, they were beautiful. Rui bent down to brush Mizuki’s hair away from their face before he scooped them up, carrying them out of the room.

Rui eventually found his way out of the mansion, squinting as his eyes adjusted to the early morning light. The sky was streaked with beautiful pink hues, reminding him of the eyes that lay closed in his arms, never to open again. He looked down at Mizuki’s face, a silent tear falling from his eye and landing on her cheek.

“My, Mizuki,” Rui said softly, “I wish you could see this sunrise.”

Notes:

sorry