Chairman Kuroshio is a powerful corporate executive and owner of a prominent shipyard. After a traffic accident, he and his wife are aided by the Arashiyama family, who help them take shelter in an abandoned mansion during a thunderstorm. When a giant robot attack destroys much of the city and kills numerous civilians, including Hayato Arashiyama's parents, Kuroshio adopts the orphaned Hayato and organizes a volunteer defense force to combat the Phantom Ship.

Beneath this philanthropic facade, Kuroshio conceals a secret underground war factory located beneath his residence. His true motives are driven by greed and a desire for power, seeking to destroy society to increase his profits. He wields significant political influence through his wealth.

Kuroshio uses a mind-controlling beverage called Boa Juice, distributed by his corporation, to manipulate civilians. Those who consume enough of the product dissolve into foam and cease to exist. Commercials for Boa Juice interrupt important news broadcasts and speeches, extending his control.

His operations involve selling arms under the guise of a government agenda. The true nature of his actions contradicts his public statements. He serves a mysterious entity connected to the Phantom Ship, though the exact nature of this relationship remains undefined. His plans are ultimately thwarted by those he deceived.