Hayato Kuroshio is a supporting member of the crew aboard the Oceanus and one of the earliest Celebrants to serve under the organization Cerebrum. In the simulated world of Maihama, he also holds a position as a student council officer at Kyo Sogoru’s high school. Kuroshio originally hails from the Shizuoka server, and prior to his current duties he was a skilled pilot who operated the prototype Zegapain unit developed by Shima. He once served as a Gunner, working under and deeply admiring Isola, but his apparition data eventually grew too unstable for entanglement, effectively ending his direct frontline role.

Kuroshio’s outlook is marked by a deep weariness from his prolonged existence as a Celebrant, and he carries a notably nihilistic perspective. His fear of true death makes him reluctant to surrender the seeming immortality of an undying apparition, and he stands apart from many comrades who seek a physical body. This dread even leads him to suggest surrendering to the Gards-orm rather than risking the unknown. However, after discovering Shima’s true identity, Kuroshio undergoes a significant shift. He abandons his defeatism and resolves to strive toward genuine living alongside Kyo and the rest of the crew.

In battle, Kuroshio’s past as a Gunner and his experience with the prototype Zegapain grant him considerable combat insight, even though he no longer pilots regularly. He later takes part in coordinated defensive actions when Sin and Abyss invade the Maihama server, working with Minato, Irie, and others to help contain the Deutera areas. His core relationships are defined by his respect for Isola and a professional bond with the Oceanus team, particularly Shima and Kyo. Through his gradual acceptance of life’s fragility, Kuroshio moves from a state of fearful paralysis to active dedication, becoming a quietly determined contributor to the fight for humanity’s future.