Keisuke Nago is a major character in the tokusatsu series Kamen Rider Kiva. He is the main user of the Kamen Rider Ixa system, acting as a skilled and determined Fangire Hunter. Nago is driven by his strong sense of justice and strict moral code, which sometimes puts him at odds with others. Throughout the series, his character grows from being rigid and self-righteous to more understanding and cooperative, playing a crucial role in the battle against the Fangire threat.