Master Sergeant Otoha Sakurano is a master with the sword, but is otherwise an unknown in her abilities. She comes from an island where her family runs a dojo. She is naive and usually a cheerful girl, although she gets pretty violent with Ryohei Tachibana whenever he says something perverted. Even so, she appears to have feelings for him. Her Sonic Diver Unit is named Reijin, but she nicknames it "Zero".
She is voiced by Ayako Kawasumi.