Masao

was a Flame Human, affected by the Human Body Ignition Phenomenon.

Appearance
As a Flame Human, Masao had a lean figure, charcoal-coloured skin, rugged teeth, blank eyes with no pupils and flames on the ankles, elbows and scalp.

VS. 1st Special Fire Brigade arc
Masao was seen causing havoc in the city, until the 8th Special Fire Brigade arrived to deal with the life-threatening situation. With Shinra's help, Akitaru was able to pierce through Masao's body with his Core Annihilating Pile Bunker. Afterwards, the death of Masao caused backlash from a bystander, who furiously ordered Akitaru to return Masao back to her.