Matt Kwasniewski-Kelvin, a founding guitarist of the acclaimed London post-punk band Black Midi, has died. He was 26. In statement from the guitarist’s family, posted by band’s label Rough Trade on Monday, they said, “It is with deep sadness that we as a family regret to inform you that Matthew Kwasniewski-Kelvin has died after a long battle with his mental health. A talented musician and a kind, loving young man finally succumbed; despite all efforts.” Kwasniewski-Kelvin met his Black Midi bandmates as a teen at the London performing arts academy BRIT School. The band performed alongside a loose crew of...