Niko Kazao is a second-year student at Daikoku Welfare Academy and appears as a supporting character. Under the national policy of arranged marriage in the story's setting, she is designated as the fiancée of Kazushige Sanda. She has long brown hair and brown eyes, and is often seen in her school uniform. Her personality is described as bold and pragmatic, with a tendency to freely chase danger and taboo experiences. Her motivation appears to be related to her desire to break free from societal restrictions and become a proper adult on her own terms. In the story, her role is tied to her relationship with Sanda, as their mandated engagement influences their interactions and the broader social dynamics of the world. She is also connected to the other students at the academy. Information about her development over the course of the series and any notable abilities she possesses is not well documented in available sources.