In 1996, Edge Of Sanity released "Crimson," a 40-minute single-track album that combined black metal, melodeath, and prog influences. The album was a result of improvisational jams with all band members present, showcasing the band's musical experimentation. Despite being hailed as a defining achievement by fans, Edge Of Sanity disbanded shortly after the album's release. "Crimson" remains a cult favorite and a benchmark for progressive death metal.
Source: https://www.loudersound.com/features/story-of-edge-of-sanity-crimson-death-metal-underrated