Beastial Flames! (Fire Force X Male Reader)

Y/n lost one of his fathers to Spontaneous Human Combustion, all he has now are his three brothers, his other father, and his uncle. Now, he's devoted himself to researching Spontaneous Human Combustion and what causes it. His brothers and father worry about him, as beneath his caring exterior is a monster waiting to be uncaged.

He is a fourth generation pryokenetic, harnessing the flames in his soul through ninjutsu and his will.

He soon ends up in Tokyo, his brothers and father following him without his knowledge. Each company sees him as a valuable ally as well as an extremely dangerous enemy if his wrath is kindled but a little.