Setsuo Miyamoto

is a former firefighter, who was turned into a Flame Human.

Appearance
As a human, Setsuo was a bald middle-aged man with a stubble and a very devious appearance. He was last seen wearing a prison uniform, given that he was a criminal. When the man fell under the Human Body Ignition Phenomenon, his skin turned dark and parts of his face, above his cheeks, disappeared, leaving a vertical lining above his mouth serving as his eyesight. He has no scalp and flames are present at the back of his head. Setsuo has a very muscular physique and wears white trousers with black shoes. The majority of his facial features are composed of his mouth, though he has no lips and his large teeth are always visible. Through the transformation, the handcuffs he was wearing turned into flames alongside him, which he uses for combat. During his encounter with the 8th Special Fire Brigade, a small part of his face was blown off by Takehisa Hinawa and one of his arms was cut off by Shinra Kusakabe.

Personality
As a human, Setsuo appeared to be a troubled and psychologically disturbed man, and was dubbed insane after becoming a serial killer. He doesn't have concern for the well-being of others, as he recklessly directed his flames and burned two people, and displays ill intent. As a Flame Human, Setsuo retains his psychotic behaviour to an extent and becomes driven with killing everyone in sight, bringing them painful death in the process. Though he possesses a strong killing-intent, as he was able to keep his consciousness, he thinks about his actions tactically, proving he has some intellect, as shown when he chose to give up when faced against the 8th Special Fire Brigade, showing that he values his life dearly. Setsuo has shown to have a strong opinion on Special Fire Brigades themselves, comparing them to murderers.

Abilities
Setsuo transformed into a Flame Human while having a strong attachment to his life and, as a result, he has a notably strong consciousness and self-awareness. Using the flames around his wrists and from his head, he is able to fly and launch large fireballs at his opponents. Setsuo can also use the flaming handcuffs as malleable flames to suffocate opponents or use them for offensive attacks. He has a fit physique and has shown to be able to punch through Pusupusu Comet☆ with ease.

Background
During his time as a firefighter, Setsuo became mentally disturbed and managed to kill four innocent people for his personal amusement. In court, he acted like he lost his insanity.

Plot
On the final day of his trial, Setsuo was deemed not guilty for the actions he had done in the past, by reasons of insanity. As he leaves the court, Setsuo's hand starts to envelop in flames, a sign that Setsuo was slowly becoming a Flame Human. In the midst of his transformation, he kills two people, who were laughing at his misfortune. As he fully transforms, he declares his anger by stating that he'll kill everyone. Setsuo continues his rampage by killing an innocent person and the judge of the courthouse. He then leaves the court as he takes his lawyer hostage. He encounters Shinra and Arthur, who work together to fight him. During the fight, Setsuo notices a woman, who happens to be present on the scene, and progresses to use his flames on her, but Maki stops his attack and turns it into a fireball. When the Flame Human attempts to surrender, hoping that his life would be spared, Takehisa shoots him. In retaliation, Setsuo uses such an opportunity to distract his opponents and flee the scene, declaring that he will kill innocent people like Special Fire Brigades kill Flame Humans.

Setsuo encounters a boy and threatens to kill him, but is stopped by Shinra. The two then start their confrontation, with Shinra dominating the fight. Scared of his opponent's abilities, Setsuo attempts to attack him from behind his back, but it just leads to Setsuo getting his hand cut off by one of Shinra's kicks. When Shinra readies to attack again, Princess Hibana jumps in and stops the boy from attacking.