If the todoroki siblings were in Infinity train

Prologue

-"Today was so much fun, Shoto," Fuyumi said fondly to her younger brother as they were walking down the dark street along with Natsuo. Natsuo faked a yawn, "..Yeah but it would have been better if it weren't for some random kid pointing a laser at the screen"

As they were walking Fuyumi's phone buzzed in her coat pocket, as she pulled it out. Her expression turned into a bittersweet sigh as she looked at it. Natsuo who noticed looked at her suspiciously. "Who's it from?"

"Dad. He wants us to bring Shoto back be- She was interrupted by Natsuo, as he groaned loudly. -"Seriously?! That old man really needs to learn to let our Shoto, have some fun for once!" He unknowingly grabbed Shoto holding him by the side as if he would disappear.

Shoto looked at him with an awkward expression, as Natsou noticed as he practically flushed releasing Shoto. Shoto sighed, "Look I really appreciate what you two are trying to do for me but- A loud scream shrill scream interrupted him as the Todoroki siblings froze.

- "PLEASE LET ME GO! I'LL GIVE YOU MY MONEY! DON'T HURT ME!"

Fuyumi and Natsuo didn't hesitate to join their brother who was already running towards the scene. But what he saw made him more confused. But he didn't let his guard down, already activating his ice quirk as he was staring down the villain.

"Let that civilian go Dabi!"

Dabi rolled his eyes as he stood up with a shrug. "Relax hero. I was just getting my daily pay check" The civilian who saw this as opening quickly ran past the villain not paying any mind to the other two civilians behind the hero.

Dabi seemed to notice Fuyumi and Natsuo standing near Shoto as that only made him laugh. "What? I let him go. So now what? Gonna capture me so your siblings can take a picture?" He mocked.

Fuyumi, Natsuo, and Shoto didn't move as Shoto kept his glare on him. "You are gonna come quietly back with us to the police. If you corporate i could perhaps convince them to give you a lighter sentence for you're crimes"

"Aw.. Shoto what an amazing- hero speech!" Fuyumi and Natsuo both praised as Shoto began to blush in a bright red color.

"A pretty boring hero speech if you ask me. From someone who watched the U.A's sports festival half a year ago, seeing how you didn't want to use the old man's quirk" Dabi interrupted.

"I had enough of this guy let's just- "Take me to the police? ~Oh you three really are still glued to the whole 'Hero' society huh?" Dabi questioned as he slowly approached them.

"What are you talking about?" Fuyumi asked carefully while also allowing her quirk to turn on standing a bit closer to Shoto.

Dabi stopped. As he tapped his chin pretending he was thinking, "Oh I don't know.. Maybe a hero who protects everyone as his children rather than others. Or forcing a quirk marriage just to have a child strong enough to defeat the former number 1 hero"

The three of them froze as Fuyumi dropped her ice quirk carefully approaching dabi. "How...how do you know about that?" her voice was on the verge of breaking hoping he was just some villain that heard about it. 

"You could say I got some info from a very old friend," Dabi said with a dark grin in his eyes. Shoto created a small fire on his left side, while also having his right side ready to contain dabi in ice.

Noticing their confused and suspicious expressions, Dabi smirked as he lifted up his left hand allowing blue fire to appear.

"I'm honestly really sad it took you three this long to figure it out. But oh well! All good surprises shouldn't be rush"

"t-Toya..??" She whispered. Shoto looked at him shocked, still trying to figure out how he didn't figure out something so obviously like fire or how they shared the same shape of eyes.

Natsuo angrily stomped over to Dabi with tears in his eyes. "So this is where you've been!? Killing people, robbing everyone who you see as a weak target?? LEAVING SHOTO, FUYUMI AND I THINKING ALL THESE YEARS ARE LOST OLDER BROTHER WAS DEAD WHEN APPARENTLY HE WAS ALIVE?!!"

Dabi was taken back by his outburst as he glared. "I waited for Endeavor a whole day! Just for him to show up on the mountain. I was so upset that i didn't know that my quirk was getting out of control before i caused that fire"

"Even if that was true! Why didn't you try to call someone for help the moment you had your quirk under control?! Or at least have some decency to tell us you were still alive!"

Fuyumi sharply yelled tears were now streaming down onto her face. Her sympathetic expression was replaced by deepened glare.

Natsuo and Shoto both blinked, since they never heard her raise her own voice like that.

The tension was thick in comparison to the nice cool air when suddenly a train appeared directly behind Dabi as the train doors slowed down. They were all too stunned in shock over the reveal paying no attention to mind as The train door swung open allowing a bright flash of green that took them.

—-------

-"How's things going in the fantasy car Amelia?" One-One asked politely as the Woman was fixing her watch before she sigh. "Pretty chaotic for my taste, but overall pretty good could use a few more magical animals and less fairies"

"I knew adding that many fairies would be a bad idea" The negative One-One said. Suddenly four passengers arrived all at the exact same time as they were sliding down to where One-One and Amelia were. Amelia looked at them with a confused expression.

"Even after my days as a conductor i never saw anything like this" She whispered. One-One clapped excitedly.

-"I know right?! Four new problems that could be solved here on the train to provide them each a better future! -"Or their life must have been tragic or simply boring considering it's the four of them" The negative One-One added.

"Couldn't be even stranger than this" Amelia mumbled, before she took a closer look at them. "Hmm. They must be related considering how this younger teen appears to have his head half red and white while the other two match him." She said walking alongside where the new passengers laid.

"However this blacked hair one doesn't seem to be related to any of them. Unless he's a close friend or something"

One-One hummed. "If that's the case. I wouldn't want the four of them to explore this train if they aren't siblings. I can't bear the thought of separating such bonding potential" The positive One-One spoke dramatically.

One-One pressed a button calling forth the machine as it grabbed the younger's teen right hand writing a number before repeating this process with the next person

Amelia watched, never taking her eyes off the progress of it. "I still can't understand how you managed to not get bored so easily during stuff like this" One-One looked at Amelia. "I don't like to think of it as boring but rather people coming from the real world to grow and learn about themselves and each other"

"Like therapy" The negative One-One added once again. Amelia couldn't help but laugh, as the Machine finished the last number.

Each of the vehicles began to disappear as the train appeared from below moving fast across the train disappearing from there eye view.

Preview for the next Chapter,

The four of them wake up in a strange place, seeing beach along with strange numbers written on the palm of there hands. Especially when a Mysterious cat shows up saying there now on the train 

This story is also cross posted on Archive of our Own! ^^