Two Flashfires

Inside the police station, Officer Gori walks the cell block while Dr. Garaki asks whether the final battle has begun. Told to be quiet, the doctor notes there are fewer officers on duty than usual, which answers the question for him. Thinking of Dabi, he reflects that his years spent hunting for "seeds" born warped enough to serve as vessels were all aimed at a day like this.

The story goes back to Sekoto Peak, where a young Toya, abandoned by a father who promised to come, sets himself and the mountain burning during a breakdown. He falls and lands in a riverbank that extinguishes him, leaving him alive but burned across every part of his body, shaking in agony on the ground while All For One watches from a distance.

He wakes in an orphanage infirmary, older, with patches of reddish wrinkled skin under his eyes and across his ears, chest, and jaw. The children in the play area are glad he is finally up. He starts to ask where he is and stops when he cannot recognize his own voice, then learns he has been asleep for three years. The caretaker, Mr. Sunny, tells him he cannot go home because this place is his home now. Toya spirals into denial, insisting his father must be too busy with hero work, that he owes his family an apology for what he did, and that he needs to show Endeavor how hard he has been working.

All For One cuts in through an audio-only call on a nearby monitor: heroism is out of reach, his body took meticulous work to reassemble, and his Quirk will never behave as it did, because the fire he started weakened him, wrecked his organs, and dulled nearly every sense. As the boy breaks down, the man dangles a possibility, that his people might be able to put the flames right if the boy stays and studies with them. Toya screams at him to shut up and lunges at Mr. Sunny, insisting Endeavor is the only person he will learn his Quirk from.

The recruitment fails. All For One and Garaki write him off as too broken, and too lost in his own fixations, to steer, and the entire rescue is revealed as one instance of a broader habit: cultivating backup vessels in case the relationship with Tomura soured. Toya burns the orphanage to the ground and runs, and the villains let him go, with Garaki predicting he would die within a month of waking. He lived instead, took a new name, and eventually circled back to them when Giran walked him into Tomura's circle after the Hosu Incident. In a private meeting arranged before he loosed Hood on Fukuoka, Dabi asked Garaki whether he was the one who patched him together all those years back. Garaki, surprised he worked it out, asked how he survived; Dabi ignored the question at first, saying the sight of the Nomu told him what had been intended for him, and that the place made a fine spot for a funeral. Garaki guessed that sheer hatred and resentment had held the body together.

Back on the battlefield, Dabi admits to Shoto that he did go home after the orphanage, and stopped a few steps short of his father, who was busy putting his youngest through a brutal session. Watching a family that had moved on without him, his old certainty of being a failure to the legacy bubbled back up, and he abandoned the few things he had wanted to do since waking. His skin burns hotter and darker as he explains he has drilled his Quirk relentlessly ever since, in preparation for meeting Endeavor again, helped by dead pain receptors and recordings of Endeavor at work. Shoto, holding the Ultimate Move he developed while training with his class, realizes his brother always intended to die at the end of this. Dabi, his jaw deteriorating and fresh burns spreading up his face, promises to burn everything Endeavor loves, calling it the only proof that will ever exist of his birth.

Shoto says he will end it, and Dabi opens with a sloppy but overwhelming Hell Spider aimed at the remaining heroes, then leaps behind Shoto and hammers him down with a fist wrapped in fire. Raging, he demands to know how his brother's face looked living at U.A. among people frightened of him because he is Endeavor's son and, worse, Dabi's brother. He brands him a "product of calamity", a coddled underachiever propped up by everyone around him, a half-baked puppet with no one to live up to. He finishes by knocking Shoto skyward and driving a Jet Burn through his chest, throwing him into a tower.

From the wreckage, Shoto concedes that the aimless husk part was once true, as Dabi notices his own flames going out. Shoto says he is glad his brother finally noticed someone other than their father, and that however horrible their family was, it excuses nothing done to people who had no part in it. He builds Phosphor, the Ultimate Move he designed himself: the essence of Flashfire Fist applied to both halves of his body, ice and fire balanced through the hot and cold blood in his heart to produce cold flames. Explaining it to Izuku during training, he had described using his ice to strengthen his fire rather than shield himself from it, the reverse of what his father wanted out of the Quirk Marriage, and thanked Izuku for the Sports Festival, where he learned Half-Cold Half-Hot belongs to him and not Endeavor.

Diving from the building at full charge, Shoto lands Coldflame's Pale Blade, killing the flames and dropping his brother's body temperature. Phosphor times out, Dabi springs back and sets off a Hell Minefield, and Burnin, Kido, and Onima barely blunt it before collapsing. Shoto charges another round, boosting it far past the first with everything he has gained from his friends and his father's work-study training, and drives through another torrent of fire to bury an ice-covered fist in Dabi's stomach while begging him to stop. Great Glacial Aegir snuffs the flames and freezes his brother and the surrounding buildings solid, ending the fight he has been walking toward his whole life.

Toya Todoroki's survival at Sekoto Peak is explained, along with All For One's failed attempt to groom him as a spare vessel.

Haruaki Sun-Sun and the orphanage debut in flashback, and Toya burns the facility down before escaping.

Dabi's private meeting with Garaki before the Hood attack is revealed.

Shoto unveils Phosphor, then uses Coldflame's Pale Blade and Great Glacial Aegir to defeat Dabi.

The seventh season's eighth episode, adapted from Chapters 350 through 352.

The anime shows more of the children at the doctor's orphanage, adds Toya fighting off Haruaki Sun-Sun, extends his trek home, and gives Dabi more punches during the beatdown. It also depicts him watching online footage of Endeavor's Ultimate Moves, which the manga only alludes to.