Matsuo was the firstborn child of Airi Midorikawa. Like her brother Deidara, she did not possess any long-term disease, unlike Shunsatsu and Aiko, the former of which suffered from asthma, while the other suffered from an unknown heart disorder. After Shunsatsu was born, they were seperated from each other and put into distant foster homes, where she spent her entire childhood.