Shoto Todoroki & Flaming Sidekickers vs. Dabi

Shoto & Flaming Sidekickers vs. Dabi is a battle taken place during the Second War as Heroes Shoto and the Flaming Sidekickers face against the Villain Dabi.

Prologue
After finding out that Yuga Aoyama was coerced by All For One into being his spy, the heroes devise a plan to definitively defeat All For One, Tomura Shigaraki, and their allies. Using Izuku and Yuga as bait, All For One is lured into an abandoned urban area, where the boys confront him. Believing they were all alone, All For One uses his Warping Quirk to bring the Nomu and dozens of villains to capture Izuku, but then, thanks to Neito Monoma, numerous Warp Gates appear around him, from which Heroes begin to emerge from.

Dabi is one of the villains that All For One summoned, and upon seeing his father, Endeavor, he heads to face him while taunting him. Using his Blueflame Quirk, Dabi unleashes a large flare, but is blocked by a huge wave of ice. Emerging from another Warp Gate, Shoto and Class 1-A join the battle. The heroes then activate the "Troy" defense system, and most of the villains are encased in containers that emerge from the ground. The villains don't take long to break them open, with Dabi mocking how they didn’t even last three seconds, but Shoto rebuts, saying that was all they needed.

It was all a plan to delay them long enough for the heroes to position themselves and shove the villains into several warp portals open behind them, transporting them to various locations far from each other. A team of heroes made up of Shoto, Ingenium, the Flaming Sidekickers, and several more manage to warp several villains, including Dabi and a near High End Nomu, to Kamino, where they face off.

Battle
Perched atop All Might's statue, Dabi uses his Blueflame Quirk to generate an intense flaming tornado visible for miles away, isolating Shoto inside a personalized battlefield, and keeping most of the heroes and villains away due to the intense heat. Only the Flaming Sidekickers manage to withstand it and stand by Endeavor's third son.

Outside the giant fire, the Nomu takes down several heroes with spikes it spawns from its body, completely unconcerned by the flames. Ingenium stands outside the fire tornado, worried for his classmate, unable to interfere due to the high heat threatening to damage his Engine Quirk. Inside the flames, after commenting how the fighting brings back memories of watching the Hosu Incident, Dabi focuses his attention on Shoto, Burnin, Kido, and Onima, lamenting that his father sent his little brother and his lackeys to confront him instead of doing it himself.

Onima worries about his teammate, Kido, because he can't stand the heat like the others, but he calms him down by assuring him that he uses his Traject Quirk to alter the trajectory of the blazing air away from him, plus that he doesn't plan on abandoning them after serving Endeavor for so long. Burnin supports him in his statements, making it clear that despite issues with Endeavor's past, he always got the job done, and now that he's entrusted them to Shoto, they have his full support.

Shoto thanks her for her words, and declares to Dabi that he is not there to confront him simply because their father ordered him to, but because he cannot ignore his insane and destructive warpath, and wants to stop him, which Dabi ruefully accepts. Shoto then asks his older brother why he never returned home after surviving his accident.

With the heat of his own flames tearing apart his skin and exposing his raw muscles underneath, Dabi explains he was "saved" by All For One, but he broke free and went back home, only to see his butsudan and his father harshly training Shoto, reminding him of his purpose as a failed creation. With his family having moved on without him, that day he decided that Toya died and Dabi was born in his place, and since then, his hatred and revenge have allowed him to live longer than his deteriorated body should've let him.

Dabi begins to increase the power of his flames, not caring that by doing so his body will reduced to a crisped husk, reaching temperatures that melt the All Might statue on which he stands on. Seeing this, Shoto understands that Dabi has been prepared to die from the start, as both brothers prepare their respective Quirks to perform Flashfire techniques.

The increasingly combusting Dabi is pumped after sharing his tale, while Shoto, who continues to control his fire and ice, realizes his brother is faster at raising the temperature without any hint of hesitation. Still, Shoto states he is the one who will take down Dabi. The older brother replies he has thoughts about him too, and asks Shoto if he is fan of All Might, before attacking with his own version of Flashfire Fist: Hell Spider. Dabi unleashes chaotic fire spirals that ravage the battlefield outside their personal duel in the flaming tornado.

The heroes try to avoid the flaming slashes as best they can, and Ingenium, noticing how thicker and haphazard the attack is, can't help but worry about his friend. The Flaming Sidekickers manage to protect Shoto using their respective Quirks, and Onima asks him if he's ready yet. Shoto replies he is, but at that moment Dabi appears behind him.

They shockingly realize that the Hell Spider was just a feint to allow Dabi to get close enough to his brother to melee him with a flame blast punch, knocking Shoto down with ease. Burnin tries to help Shoto, but the high temperatures of Dabi's fire prevent her from getting close. As Dabi merciless continues his assault on his little brother, He puts Shoto down with cruel remarks, lambasting him that despite being born blessed he is just a half-baked puppet unable to do anything by himself, finishing with a point-blank Jet Burn that launches Shoto high into a nearby building.

Despite the beating, to Dabi's surprise, Shoto is barely hurt, having neutralized his flaming blows with his own powers in equilibrium. Emerging form the debris, Shoto replies to Dabi that he is not completely wrong in considering him a half-baked dummy, and that he's even glad that he kept an eye on him despite his obsession with their father, because he has likewise been focusing on him, having developed a new Flashfire technique specifically to stop him.

Shoto remarks that Endeavor has been terrible as a father, and the Todoroki family is messed up because of it. However, burning people to death was Dabi’s choice, and he is not going to let him continue to take more innocent lives. Dabi reacts vigorously at the "masterpiece" as Shoto tells him to focus his hatred upon their own screwed-up family.

Shoto unleashes his Ultimate Move at him, Flashfire Fist: Phosphor, which harmonized the extreme temperatures of his two sides to allow him to use both of his Quirks throughout his body. He then uses "Icebound Crash - Coldflame's Pale Blade" to cool Dabi down and have him thrown backwards by the impact. Dabi manages to recover by shooting pillars of flame from his hands to balance himself up, realizing that Shoto’s body can withstand the heat of his Blueflames as well as avoid the drawbacks of his own fire power, making him the right person to face him.

But he doesn’t stop for a second and as he touches the ground, directing all his flames towards it, telling his youngest brother that while they share blood, they are nothing alike. Shoto can't maintain Phosphor for long, needing to prepare the technique again, leaving him open to Dabi's next attack. Dabi shouts that both follow parallel but totally opposite paths and that they represent the limit of their superhuman society.

Going berserk, Dabi unleashes the full power of his Quirk, and mainstays of blazes rise up out of the ground, heading right towards Shoto. The heat from the flames is so intense that they even manage to burn Shoto, but Burnin, Kido, and Onima jump forward and use their Quirks to protect Shoto. They don't come out unscathed, but they do manage to blunt the heat enough to give Shoto the chance to build up his fire and ice attack.

Thanking his father's sidekicks profoundly for their help and recalling his classmates support, Shoto launches forwards so fast Dabi can't react in time. He implores his brother to stop, reassuring him that they can still walk the same path. Then, he unleashes his Ultimate Move, Great Glacial Aegir, a gigantic wave of cold fire that shoots directly through his brother's chest, completely extinguishing the flames in the area and freezing every nearby building.

Aftermath
While Shoto and the Flaming Sidekickers faced Dabi, the rest of the heroes fought against the rest of the villains and the Near High-End Nomu. When Burnin announces to the entire ward that Dabi is down, they can't help but cheer and feel motivated to take down creature after having secured the accompanying Villains. While some heroes take care of the wounded and the defeated villains, the rest concentrate their efforts on defeating the Nomu who is still a dangerous foe and the only way they have to defeat it is to take advantage of their numerical superiority to overwhelm it.

A few heroes mention that they got lucky not having to face any of the Tartarus Escapees, and they need to share their luck with the others. News of Shoto's victory over Dabi reaches the Heroes' command center, who send the news to the remaining battlefields to motivate the remaining forces in their fight against the villains.

Ingenium looks over Shoto, who apologizes for stalling his engines with his last attack. Ingenium tells his friend that he has nothing to apologize for. Dabi is being carefully handled by a hero who wonders how he is still alive. While he looks unconscious, a spark ignites in Dabi's frozen stomach.