The protagonist of the series. A five dan, Rei became a professional shogi player while in middle school. His parents and sister died in a traffic accident, and after that he was taken care of by his father's friend Kouda and became his apprentice in shogi. After becoming a professional shogi player and after completing middle school, he became independent of him and decided not to attend high school. After feeling a "need" to attend school however, Rei later joined a high school after a one-year delay. He lives in the city of Rokugatsu-chou (June town).

Schwi was the first Exmachina to be introduced in Tet's story. In the story she seeks to understand the human heart and was found by Riku. She looks like a young human but with several differences, being two tails coming out from her back and other machine like features protruding from around her body. She bears many similarities with Shiro. Her behavior is similar to that of a stereotypical artificial intelligence. She can absorb and process data and intelligence very quickly and act in the appropriate manner, a unique characteristic of her race. However, she seems to have difficulty in comprehending emotions and desires, otherwise characterized by her as the heart. (Source: No Game No Life Wiki)