Kanata Nijo

A second-year high school student. He's the bassist of the band εpsilonΦ.

A popular guy that everyone adores who is always friendly and cheerful—all of which he does to ensure his brother has zero semblance of any interpersonal relationship and smash his hope to pieces. Nothing makes him happier than seeing his brother tormented by loneliness and the moments he'd glare at him with vengeful eyes full of hatred. To ensure his brother thinks of no one else but himself, he follows him everywhere he goes, but at the root of it all lies a deep love for his brother.

(Source: ARGONAVIS from BanG Dream! Wiki)