Sekirei #02 who has computer and hacking skills. Matsu was also a member of the original Disciplinary Squad.
Matsu was originally created by Takao Yoshika for use in the Sekirei manga. She has since appeared in the anime adaptations of the manga along with appearances in other media
Matsu appears in two notable items outside of the Sekirei manga and anime. She appears in the Sekirei Drama CD and in a video game based on Sekirei that was produced in 2009 for the Playstation 2 game system