Himuro, a wealthy and powerful industrialist, inherited a vast fortune and business empire. Diagnosed with a terminal illness, he fixated on achieving immortality, driving him to research legends of mermaid blood's life-extending properties. He constructed a massive underwater research facility, Himuro Heavy Industries, deploying advanced technology for extensive, unethical experiments. These involved capturing women—including Fujiko Mine—as potential mermaid descendants for testing.

Maintaining a calm, calculating, and detached demeanor, Himuro treated others as tools to further his goal. He commanded skilled mercenaries and scientists, wielding sophisticated medical and combat technology within his base. His pursuit culminated in capturing the legendary mermaid. After extracting and transfusing her blood, he initially gained renewed vitality, seemingly reversing his illness.

The mermaid's blood proved unstable in humans, causing rapid physical deterioration and grotesque mutation. Despite his horrific transformation, Himuro's obsession persisted; he pursued the escaping mermaid as the sole remaining hope for a cure. His degradation accelerated uncontrollably in the collapsing facility. Ultimately, his mutated body dissolved into the ocean as the ruins consumed his legacy and resources.