Author Notes:

Heya, so this is the first fanfic I've ever written and I'm excited about it though it might not be too good and there'll probably some grammar mistakes here and there because I'm proofreading it by myself. Ideas and suggestions for this story are welcome along with good and reasonable criticism.

About the story:

I wanted to try writing this story because I couldn't get the idea out of my head. I love the world of MHA and I really like Tsuna because I think he's cool especially when he goes into Hyper Dying Will mode so I thought why not make a crossover with them as my first fanfic. Oh, and Tsuna will be a bit different from the original series because he's older and will be more self-confident so he might seem a bit OC but he won't be a whole new character...well I hope not...

Welp Without Further Ado Let It Begin

When I was young I never had any talents or hobbies, I couldn't do anything properly so I was nicknamed 'No-Good Tsuna', it used to make me feel bad, but now I find the nickname nostalgic.

I hardly had any friends and I was looked down upon by most of my peers, then an infant in a suit with a fedora named Reborn came into my life.

He wanted me to become the head of the Vongola Famiglia, the strongest Mafia Family, and so he became my tutor of sorts despite my constant protests.

It was bizarre how a baby could be a hitman of the mafia but then again, even the mafia wasn't quite what I was expecting.

It was because of Reborn that I had gained my strange powers and it was mostly thanks to him that I had to fight a lot of battles against dangerous people with my friends by my side.

My dear friends...

I wouldn't hesitate to call any of them my family. They stood by my side and choose me to lead them, they believed in me even though I didn't. Even Reborn, he guided me and believed that I could be something great (Maybe). He was ruthless with me and made me go through hell but I owe everything that I am to him and I consider him as a great friend.

I would do anything for my friends and protect them from any kind of danger as they did for me.

I wish I could have lived longer to stay with them...

At the age of 26, I was bedridden because of an unknown disease which led to my death.

Still, I was happy on my deathbed because of all my dear friends who were there with tears in their eyes. They were sad because of me but they were healthy and I knew that they would live on even without me so even though I had my regrets, I can say I was happy with my life.

Therefore when I closed my eyes, I was ready to move on...

Though I sure wasn't ready to see Byakuran standing in front of me while eating marshmallows in a white void of sorts with nothing in sight except me and him.

"Yo, Tsuna." The man said with a shit-eating grin on his face while waving.

"Byakuran...I must have committed some terrible sin and got sent to hell when I died" Tsuna knew that Byakuran had something with this but he didn't want to him any satisfaction.

"Ah!...what's that supposed to mean you meanie" Byakuran pouted which made him seem childish.

Tsuna couldn't help but laugh at his usual antics.

"Hey! Stop laughing! I'll cry ya know!" Tears were even starting to form in his eyes.

"Alright alright, I'm sorry". Being the boss of a Mafia gang along with Reborn's guidance (tortures and threats) made Tsuna calmer and less prone to panic than when he was younger, Reborn also forced him to develop the habit of trying to gain the upper hand in unknown situations like this even with close companions.

"Its good to see you, old friend." Though Byakuran was once an enemy, he has helped Tsuna enough times to be considered a good friend so he gave him a warm smile.

"Grh..." Byakuran turned away while slightly blushing. Because of using the Hyper Dying Will Mode numerous times Tsuna's appearance started changing as he became older, his eyes were now orange and sharp along with his facial features yet he looked warm and welcoming, he was of average height and he looked slender but underneath his clothes were toned muscles gained from numerous battles and training, he had an air of confidence about him which made him seem reliable and strong along with a calm and cool demeanor. All of this made Tsuna a very charming man who looked attractive to females and even males since he had a kind of cool feminine beauty to his face so Byakuran could in no way be blamed for his reaction. 'No really, I'm straight goddamnit!'

"Byakuran?"

"Hahhh" Byakuran let out a sigh and mumbled, "You've changed way too much Tsuna..."

"What was that?"

"Just...nothing..." Byakuran turned to Tsuna again. "Anyway, let's get back on track, I'm sure you're wondering where you are and why I'm here" Byakuran's face became more serious. "You were dying Tsuna, well you're already kind of dead right now."

"Kind of?"

"Yes, Tsuna" Byakuran nodded grimly. "Because of that disease, you became ill and you were about to die. Nobody knew anything about it and it couldn't even be cured by the flames, there was nothing we nor the Arcobaleno could do to help you." Byakuran grimaced a little and he seemed regretful. Tsuna didn't blame anyone for his condition, he was grateful that they tried so hard for him yet the others couldn't help but blame themselves for their powerlessness.

"Byakuran..." Tsuna was cut off by Byakuran holding out his hand.

Byakuran took a breath and continued, "But even after all that, none of us gave up. So with Uni helping me, I used the power of the Trinisette to save you but there was nothing I could do in our world..." Byakuran paused for a few seconds but before Tsuna could speak he continued again, "You deserve better Tsuna, after everything you've done and for all the people you've helped."

Then Byakuran suddenly smiled again and pointed his finger to Tsuna.

"So, Sawada Tsunayoshi, you get a second chance at life while being reincarnated in a parallel world!"

Tsuna was taken aback by this but his only reaction was slightly raising his eyebrows.

"Like it? It's an idea I got from a manga, this parallel world is really interesting, it seems I don't exist there nor anyone else you know for that matter. It's the same as our world but it's entirely different from ours and- ah it looks like we're running out of time, damn I was taking too long."

"What..." Tsuna then noticed that his body was beginning to fade into particles or something.

"Ah whatever I'm sure you can handle whatever comes your way. Also, don't worry about being a baby again, you won't get your memories until your brain can process them again, you can thank Uni for thinking of that. Oh, and by the way, Dying Will Flames don't exist there so I modified some things to make you more suitable for that world. You can thank me for that." Byakuran gave a wink with a smile.

"Oi...wait a minute..." Tsuna knew he lost control of the flow but he couldn't find the energy to say much anymore.

Byakuran's smile then became softer and his eyes seemed a bit sad, "Enjoy yourself Tsuna, live your life to the fullest this time and get a girlfriend or something, you're wasting that pretty face of yours!"

Tsuna had more things to say but he just gave an exasperated sigh, "Goodbye then, old friend, thank you and give my thanks to Uni, take care of her...along with everyone else..." Tsuna chose to say his goodbyes and thanks for their efforts as he started losing his conscience.

"Yeah...don't worry about your family we'll take care of them...thank you for everything too. Farewell, my dear friend..."

Tsuna's whole body finally disappeared as he fell asleep.

Author Notes:

So how was it? Good? Horrible? Too long or too short? Be sure to give your thoughts in the reviews or pm me for other things you might want to tell me about, I'm not exactly satisfied with it but I don't really know how to make it different, maybe when I get better at writing I'll come back and see what I can do.

And yeah I don't really have an explanation for how Byakuya can do what he did. Hopefully, I won't use anymore asspulls.

*SPOILER, SORT OF, NBD REALLY*

I'm planning to put Tsuna in class 1-B, I want to explore the world more besides just the protagonists and I feel that 1-A has already been covered a lot. It's a risky move especially for a new author like me but I want to try it.

Also, I'm planning to use a character from a different series, Kuroki Tomoko from Watamote. Yeah, you know where I'm going with this. What, I like her, Nuff said.

Peace~