Kouhei Hayasaka

A third-year university student studying engineering. He's the bassist of the band Fujin RIZING!.

The band leader who looks after everyone as the trusted senior member. He's been called "Kou-nii" since the group was small and it stuck. While usually a calm and kind person, he gets rather terrifying when mad. He possesses extraordinary superhuman strength but avoids any and all household appliances due to his clumsy nature. The others members try to keep him from spicy foods because it can change people...

(Source: ARGONAVIS from BanG Dream! Wiki)