Nagare Banjōji, who transforms into Kizuna Blue, is one of the main characters in the series. He is the heir to the Banjoji Group and serves as the young president of an IT company, being 24 years old. Physically, he is tall and wears glasses, with mid-length blue hair cut in a bob style and sapphire blue eyes. His personality is marked by loyalty, responsibility, and a hard-working nature, often seeking reassurance and stability. He possesses a passionate and innovative demeanor, with a presence that resembles an anime protagonist, and he is known for revolutionizing the industry with his ideas. As the blue ranger and second-in-command of the Kizuna Five, his primary motivation is to support the team and uphold justice alongside the leader Tōgo Asagaki, Kizuna Red. In the story, Nagare plays a supporting role, operating primarily in the original world and occasionally appearing in the other world to assist his comrades. His key relationships are with the other members of the Kizuna Five, particularly the leader, as they work together to combat threats. While specific details of his development are limited, he remains a steadfast and capable ally. Notable abilities include the power to transform into Kizuna Blue, which grants him enhanced combat capabilities and access to ranger-specific gear, allowing him to fight effectively as part of the sentai team.