Saeko

was the wife of a factory manager. She was infected by the Human Body Ignition Phenomenon, turning her into a Flame Human.

Appearance
As a Flame Human, Saeko had flowing fiery hair, black charcoal-like skin, with the rest of her body being enveloped in flames, no mouth and solid-coloured eyes with black sclera. She was of lean figure and agile on her feet.

Personality
As a Flame Human, Saeko showed peculiar intelligence. As usual to Flame Humans, she was driven by rampage and chaos, and burned everything in sight. She was protective of her the Kawaguchi Metal Fittings Corporation, quite possibly to her husband's affiliation with the building. In battle, she was very cautious of her surroundings.

Introduction arc
Saeko, as a Flame Human, goes berserk in her husband's workplace, forcing the 8th Special Fire Brigade to arrive at the scene, to rescue the employees inside. Sneaking up behind Shinra, she absorbs the flames around jer and strikes the boy, blowing him away and leaving him unconscious. As Shinra regains awareness, Saeko rushes towards the brigade. She is stopped by Akitaru, with Maki blasting away the flames to prevent her team-mate from getting burnt. The man then uses his weapon attack, aiming to impale the being's core, but Saeko counterattacks and hits the weapon out of his hands, forcing the brigade to separate to safety. As Shinra recalls his past and promise to his mother, the boy charges towards Saeko with a blazing kick, successfully impaling her core and killing her, thus sending the woman's soul off into the "raging flames". When the brigade leaves the factory, Saeko's husband, who was waiting outside, bursts into tears while thanking Shinra that the team was able to send his wife off peacefully.