Katekyo Hitman Reborn, the awesome manga I can't find myself ever getting tired of reading, belongs solely to its creator which is, sadly, not me.

This fanfiction is held after the manga—meaning, the Arcobalenos are de-cursed and Tsuna's awesomeness knows no bounds. Okay, the first part is solely based on how Reborn's and Tsuna's relationship changes over the years. I hope you guys enjoy! This is going to be R27 friendship since I really like the Tutor-Student relationship the both of them have.

Summary: As Tsuna looked at Reborn's twelve year old self, he realized how much of an irony this situation actually was. Time travel. Post-manga.

When he was fourteen, nearing High School, it happened again.

His second kill.

(Or was it his third? Did Daemon count, since he was supposed to have died four hundred years ago? Tsuna hoped it didn't).

The sun had been setting. Gokudera and Yamamoto hadn't been with him since the former had some errands to do and the latter was back at school, practicing for his upcoming tournament. Tsuna had been walking back from school, I-Pin in his arms, wondering about something or the other, when a man had grabbed him by his arm, slammed him against the wall of an alley, pressing a gun to his temple.

"Good day, Decimo," the man greeted him with a lecherous grin, grabbing I-Pin as the child had tried to struggle, slamming her small form onto the wall opposite.

Tsuna couldn't see the man's face since it was covered, but that didn't matter, because I-Pin was there, body still, blood trailing down from where her head had hit the wall, injured, and the man's gun was now pointed at her, and oh God she's still a kid—

Tsuna burned the his face, pushed the screaming man against the wall, and, with dexterity he had no idea he had, grabbed the gun, pulled the trigger—

When he returned home, pale and shaken, blood not belonging to his own body soaking his shirt, Reborn gave him one, curt glance, asked Bianchi to extract an unconscious I-Pin from the brunette's arms, before steering the fourteen year old towards the bathroom.

Reborn's voice was oddly soothing, "Feel lucky that Maman, Fuuta and the cow are out. Take a bath and clean yourself and tell me where the body is."

Tsuna flinched at the mention of 'body', but obliged to both of Reborn's orders. Reborn left to talk to Bianchi about something; probably to remove the body since, when Tsuna emerged, Bianchi was nowhere to be seen.

Reborn handed him a mug of hot chocolate which Tsuna dazedly took, placing it on the table distractedly. He didn't dare to take a gulp of it yet, not wanting to vomit it out and have Reborn coming for his head for disrespecting him.

"You do realize that you will have to kill again, don't you?" Reborn asked quietly.

Tsuna exhaled out, brows bunching together, staring up at the ceiling. Yes, he knew that, of course he knew that. He knew he'd have to take lives again and again; hell, he already had when he had just turned fourteen, flung into an apocalyptic future with no way out.

"Yeah, I know," he mumbled.

Reborn looked at him, nodded, and then glanced at the cup of hot chocolate. Reborn was telling him to drink it, Tsuna knew, so he sipped it, finding the sweetness inexplicably soothing. He took another sip. Something about the situation in general was very wrong and frighteningly worrying. Surreal, in a way. Here he was, drinking hot chocolate, when he had just killed someone a little over ten minutes ago.

Something twisted in his stomach.

"He… the man… he had I-Pin at gun point and I…" he took in a deep breath and spoke, "He would have killed I-Pin."

It might have sounded like he was trying to justify himself, but he wasn't. His family was in danger, and that's what mattered. He didn't regret killing the man, so there was no need of a justification.

Reborn understood that and Tsuna was glad for it.

At the age of fifteen, Tsuna became the youngest person to ever take up the mantle to become the Vongola leader; the youngest Boss of any Famiglia in the underworld.

Because that was what Reborn had wanted, and it was a known fact that whatever Reborn wanted, Reborn always got.

It was kind of depressing, really.

What was more depressing, however, was the fact that he was the Neo Vongola Primo. He was actually the Neo Vongola Primo, and he had never had the option to turn down that fucking title. So he cried.

It wasn't the sort of sobbing he recalled himself doing quite often before—the sort of sobbing where his expression would morph into terror and the thoughts of 'I don't want to do this, why the hell do I have to do this, this is Reborn't fault, hiiiii!' would run through his head.

He cried because he regretted.

He regretted getting the others involved into this mess—this mess which was supposed to be solely his. This mess where only death of others meant survival, this utter and complete pandemonium that would never leave his friends, his family, the people he would happily give his life to protect. The people who meant the world to him and some more.

Reborn stayed with him that night, slept on the bed that apparently 'belonged' to Tsuna now that he had officially taken over the Vongola, his still-infant-like-but-slightly-taller body lying warmly beside Tsuna's. The hitman did not say anything, did not call him pathetic for soaking the pillow with salty water; just listened to Tsuna's unspoken words, a tiny hand lying lightly on Tsuna's head.

It was all Tsuna needed, really.

He could start being the Neo Vongola Primo tomorrow.

The Ninth had agreed to allow Tsuna to stay in Namimori, despite the brunette officially having taken over the title of the Leader of Vongola.

"You're still in High School, Tsunayoshi-kun," Nono had said, "I want you to live a normal life for a few years."

Nono said 'normal', but, fact was, his life could never be normal. Over the course of four months, he had already assassinated five more, and Tsuna, feeling quite sick, realized that he was getting disturbingly used to this.

Still, Tsuna was hell bent on changing the Vongola—and the mafia along with it. The day after his 'pitiful and really pathetic crying' (Reborn's words), Tsuna had sucked it up, braced himself, and worked day and night, travelling to Italy and back again over and over again, to do just that. Change the Vongola or destroy it—such was the fate of the world's largest and most influential Criminal Empire.

Paperwork, numerous cups of coffee, followed by Reborn's always required help and his friends' support had Tsuna changing the Vongola for better—within the next two years, a few months before Tsuna turned eighteen, the Vongola resembled a part Mafia and a part law enforcement syndicate, much stronger and much more influential than what it had been previously, with a serious leaning towards vigilantism.

Reborn was immensely proud—Tsuna could see it in the ten year old whenever the hitman looked at him (making Tsuna resist the urge to give a dopey grin)—but never mentioned it, and Tsuna was oddly alright with that.

At the age of eighteen, still residing in the town of Namimori, Tsuna languidly climbed down the stairs after only two hours of sleep. He had been completing paperwork to the point of exhaustion last night and most of the morning, away from the watchful eyes of Reborn who had, after coming to the realization that Tsuna regularly pulled up all-nighters to make Vongola a better Empire, threatened him to go to sleep, or else…

Really, the situation was so different from what it used to be previously that it made Tsuna laugh.

Anyway, as he entered the kitchen, placed a good morning kiss on his mother's forehead, his eyes fell on Reborn.

There was nothing out of the ordinary with the hitman—the fedora wearing tutor, now resembling a thirteen year old, was reading a newspaper like he always did. But something was odd—something about Reborn made Tsuna remember a man he had seen at the age of fourteen, tall with dark eyes and an even darker smile, wearing a black suite, a fedora perched on his head, brandishing a gun, saying the words come die in an instant and—

Oh.

Ohhhh.

Reborn looked up, raised an eyebrow at Tsuna's incredulous expression and smirked, "Took you long enough, Dame-Tsuna."

Tsuna shut his mouth and gave a genuine smile, "Thanks for the help, Reborn."

Reborn's smirk widened, "Don't get used to it."

Tsuna laughed.

"Hey Reborn, why do you use a gun?"

Reborn looked at him, "Is that really a question you're asking me now?"

"The Italian Police is dubbing this particular mission as 'impossible', Reborn and both of us know that that shouldn't really worry us. I'm just curious."

"The gun was the first weapon I used. That's it."

"You were taught?"

"Obviously."

"Who was your tutor? How did you meet him? Is he still alive?"

"What is this, twenty questions?"

"…No. Curious."

"Curiosity kills the cat, Dame-Tsuna. You should know that."

"Wow, you're such a hypocrite, Reborn."

"Too mouthy, aren't you? We'll have to rectify that in your next training session which will take place in the next twenty minutes. Be prepared."

Tsuna rolled his eyes and yelped when Rebon sent a book flying towards him, "You're digressing."

"Don't want to tell you, that doesn't matter, and I don't know."

"What was he or she like?"

"He was a good teacher," Reborn shrugged, and Tsuna noticed the lightly faraway look in the ex-Arcobaleno's eyes, "But he disappeared one day."

"Just like that?"

Reborn nodded in confirmation, and looked at Tsuna. And continued looking.

Tsuna shifted under the other's gaze, "What?"

"…Nothing," Reborn said slowly, worrying Tsuna about the Sun user's mental health.

Before he could have voiced his worry, a light clattering noise—that of keys falling— came from outside of the room they were currently residing in. Somebody cursed, and Tsuna could see the thin, slanted shadow spilling into the hotel room, readying himself. To his side, Reborn held a far less subtle AK-47 as compared to Tsuna's .45.

The door opened, and the cards fell into place.

"You are getting far too cocky, Dame-Tsuna."

"Well, you're still a minor. Only seventeen," Tsuna shot back, trying to smother an amused smile.

Reborn had tried having champagne again, only to have the glass snatched from his hands by one Nana Sawada who had, after giving Reborn a disappointed stare, had non-verbally threatened to hit him with a frying pan. Reborn's expression had been that of hidden terror at the woman's wrath; Tsuna hadn't stopped laughing since.

Reborn hit the twenty two year old with a paper weight plucked from the brunette's table when Tsuna's laughter showed no signs of ever disappearing.

There was fire all around him.

And his Aramani suit had coffee all over it.

Armani. Suit.

"Shit, Reborn's going to kill me," he cursed, staring, with no little amount of horror, at the brown stain on his suit.

Giving a sigh of despair, he mentally made a note to brace himself for the future scandalized looks he would definitely get from anyone who cared (which was everyone in his family, frankly speaking, with the exception of Tsuna; why and how the hell they were so interested in branded clothes was still a mystery—and would always remain as that—to Tsuna). Kyoko, Haru, Hana and Lambo would be after his head, and Gokudera would stare at him wide-eyed, refusing to say anything lest it insulted Tsuna in some manner or form—this was infinitely worse, Tsuna felt. And Bianchi.

God, Bianchi. She'd feed him poison.

He stared at the stain despondently, heaving out yet another sigh. The heat wasn't bothering him as much as it would have surely bothered a normal human being, which was a definite plus.

A half empty cup in one hand, the Neo Vongola Primo looked around appraisingly. He was in a warehouse of some sort, he could tell, frowning lightly.

The main question was:

"How did I get here?"

Reborn could be involved—for all he knew, the ex-Arcobaleno was probably trying to kill him with fire. In case that wouldend up working, the hitman would probably be laughing his ass off at the irony of the whole situation. Nonetheless, Tsuna was pretty sure that he had, after dodging over-protective Guardians, rushed to the nearest café in hopes of buying a cup of coffee. Judging by the stain blooming over his suit and the cup of warm liquid clasped in his hand, it was obvious that he had succeeded in that endeavor.

He stared at the deep, brown liquid, chugged it down in one go and tossed the cup into the fire.

"Nothing's better than a good cup of coffee," Tsuna said loudly, relieved.

And then he heard something.

A soft, muffled groan he would have missed if it weren't for his Hyper Awareness that came with having Primo's blood running through his veins.

He looked around, eyes searcing rapidly, and the groan resounded again. He pinpointed the general location of the sound, wasting no time to dash over to the place, unconsciously freezing the flames which tried to lick his skin.

Where he was and how he had gotten here didn't matter; if someone was trapped here with no way out, he needed to save said someone. He paused when he found a wiggling body, bound and gagged, in the corner of the warehouse, surrounded by fire.

"Are you alright?" he asked rhetorically, knowing that the question was redundant—the ten year old kid was burnt, not too badly, but burnt nonetheless.

But then the kid looked at him, eyes dark like an abyss locking with soft brown ones; Tsuna's breath hitched, eyes widening. He knew the eyes, knew the face, had seen it every day for the past nine years.

These eyes, however, held no recognition. But Tsuna didn't care; he knew who the kid was.

Reborn.

So, what do you think? I will, of course, continue with this fic depending on what you guys say about it, so please leave a review on your way out!