Yasuharu Takanashi
The background music for the series was composed by Yasuharu Takanashi. For the first season, two pieces of theme music were used. The opening theme, titled "Blade of Hope", is performed by the voice actress unit sweet ARMS. The ending theme is "Still Sis" performed by Kaori Sadohara. For the second season, two pieces of theme music were used. The opening theme is "Over The Testament", performed by Metamorphose, a unit consisting of singers Yoko Ishida, Kaori Oda, Aki Misato and Megumi Ogata. 5 versions of the song are played over the 11 episodes, with Yoko Ishida singing Ver.1, Kaori Oda singing Ver.2, Aki Misato singing Ver.3, Megumi Ogata singing Ver.4 and the group singing Ver.5. The ending theme is "Temperature" performed by Dual Flare, a duo consisting of singer Yuki Yamada and voice actress Natsumi Yamada.