Nero is a seven-year-old girl with black hair and the younger twin sister of Leu. She is the beloved daughter of Shiu, one of the skilled torturers at the Spirytus company. Nero has a laid-back personality and moves through life at her own relaxed pace. She attends elementary school and has a particular fondness for the color white, explaining that it reminds her of her father and of a colleague named Reu. In the story, Nero appears in a scene where Shiu calls his coworker Cero to help win prizes for her and her sister at an arcade, as Shiu is not good at the games. Both Nero and Leu take a liking to Cero, leading Shiu to insist that Cero join future playdates. As a supporting character, Nero offers a glimpse into Shiu’s personal life, showing his caring side outside of his brutal work. She does not have any special abilities or a pronounced character arc; her role is primarily to highlight the softer, familial relationships within the otherwise dark and comedic setting. Her key relationships are with her father Shiu, her twin sister Leu, and Cero, with whom she enjoys spending time.