“A couple of hundreds of years ago that was the average lifespan, forty years,” says veteran vocalist Attila Csihar. “It’s kind of surreal to say that number. It’s interesting how music ...

Mayhem, from left: Hellhammer (Jan Axel Blomberg), Ghul (Charles Hedger), Attila Csihar, Necrobutcher (Jorn Stubberud) and Teloch (Morten Bergeton Iversen).Credit...Lyndon French for The New York ...