Kiyotaka Ubuka serves as the Chief Cabinet Secretary for the Japanese government, a high-ranking administrative position that places him at the center of the nation's response to the sudden appearance of the enigmatic cube known as Kado. As a lead manager of the government's crisis coordination, he is a serious and professional figure trained to handle immense pressure, often maintaining his composure even as the situation escalates beyond conventional understanding. While the direct negotiator with the otherworldly being is Kojiro Shindo, Ubuka acts as a key strategic player within the government, tasked with determining the potential threat of the object and formulating a plan of action alongside other officials.

Ubuka is driven by a strong sense of duty and responsibility, embodying the traits of a logical and analytical mind. He is decisive, often approaching problems with a rational mindset and a focus on the big picture, which makes him an effective crisis manager. Despite his competence, he is not without personal struggles that add depth to his stoic exterior. His past includes the tragic death of his wife in a car accident, which left him to raise their daughter alone. He frequently reflects on his perceived failures as a husband and father, contemplating how to make up for lost time, a vulnerability that makes him a more relatable figure.

Throughout the unfolding drama of the series, Ubuka's role evolves from a background government official to a crucial player in the events that determine the safety of humanity. He becomes deeply involved in the mystery surrounding Kado and begins to question the motives of those around him, learning that the stakes are far greater than just national security. His professional relationships are largely defined by his position within the governmental hierarchy, working alongside other officials like Naoki Sasauchi and Ritsu Natsume as they navigate the unprecedented first contact scenario. While the official records of his specific actions and character development beyond his title and physical description are limited, his presence provides a grounded perspective on the political and personal ramifications of the extraordinary events.