Setsuo Miyamoto

is a former firefighter turned Flame Human.

Appearance
As a human, Setsuo was a bald middle-aged man with stubble and a very devious appearance. Falling under the Human Body Ignition Phenomenon, Setsuo's skin burned red and parts of his face disappeared, mainly from his cheeks above, only leaving a vertical lining above his mouth, similar to the appearance of an insect. He has a large mouth and where his eyes had disappeared had been replaced by flames flowing out from the center of his head. He gained a muscular physique, and wears white trousers with black shoes. Different from other Flame Humans, Setsuo's Flame Human form has not shown to have his body on fire other than the flames on his head. Through the spontaneous transformation, his handcuffs turned into flames that are wrapped around his wrists like a horizontal "8" with flares at the ends.

Personality
Setsuo appeared to be a troubled and disturbed man psychologically, as he was dubbed insane after killing four innocent people. He doesn't care about anybody's well-being, as he recklessly directed his flames and burned two people. As a Flame Human, Setsuo declared that he wanted to kill everybody with a painful death.

Abilities
Setsuo has shown the proficiency to speak and have self-awareness.

Background
During his time in the brigade, Miyamoto was mentally disturbed and killed four innocent people. After being caught and put on trial, he acted as he lost his insanity.

Introduction arc
On the final day of his trial, Miyamoto was deemed not guilty for his actions by reason of "insanity". As he was leaving, his hand began igniting, leading to him and everyone around him panicking as he began turning into a Flame Human. During the transformation, Miyamoto kills a bystander who was laughing at his misfortune before completing transforming.