Kurokawa is a supporting character who serves as the leader of the aircraft design team at the Mitsubishi Aircraft Company, directly supervising the protagonist Jiro Horikoshi during the early years of his engineering career. He is presented as a short man with intense, stern features and a commanding presence, reflecting the pressure of the institutional environment. His role involves overseeing key projects, including the development of the 1MF9 fighter plane, and he constantly drives his team to meet the demanding performance requirements set by the military. Kurokawa is defined by a pragmatic, no-nonsense approach to engineering that contrasts with Jiro's dreamy idealism; he functions as a grounded, authoritative figure who keeps the team focused on the practical realities of production.

Beneath his harsh exterior, Kurokawa demonstrates genuine loyalty and a protective instinct toward Jiro. When Jiro becomes a person of interest to the Japanese secret police, Kurokawa risks his own position by hiding him in his home, allowing Jiro to continue his crucial design work for the navy. This act of sheltering evolves into deeper personal support: Kurokawa and his wife provide a safe space for Jiro and Naoko's relationship, and they eventually host the couple's wedding in their home. His character arc thus shifts from that of a demanding, often frustrated boss to a reliable ally and fatherly figure, adding a layer of humanity to the corporate and military machinery.

In terms of personality, Kurokawa is frequently intense, critical, and high-strung, often reacting with frantic energy when deadlines or technical obstacles arise. Despite the gruffness, his actions reveal a strong sense of responsibility and a deep commitment to both his colleagues and Japan's technological progress. He embodies the immense institutional pressure faced by engineers in the pre-war era, as the nation raced to close the gap with Western aviation powers. At the same time, he remains a steadfast supporter of Jiro's genius, enabling the creation of beautiful machines while implicitly accepting their eventual use as instruments of war. This positions him as a key figure who bridges the gap between the pure, artistic dream of flight and the harsh, industrial reality of the time.

Kurokawa's key relationships center on Jiro and his own wife. With Jiro, the dynamic begins as strictly hierarchical but matures into a bond of trust and mutual respect, with Kurokawa acting as both mentor and protector. His wife is depicted as a gentle, warm presence who complements his stern demeanor, and together they provide crucial domestic stability for the young couple. While Kurokawa does not undergo a dramatic transformation, his development is visible in the gradual softening of his approach and the willingness to shelter Jiro outside of professional obligations. His notable abilities include firm leadership, a keen understanding of aeronautical engineering management, and the capacity to navigate the intense deadlines and political pressures of the military-industrial context without abandoning the people working under him.