Avant-garde vocalist Diamanda Galás’s fifth album is the concluding volume in her Masque Of The Red Death trilogy which began with 1986’s The Divine Punishment and Saint Of The Pit, released in June and November 1986 respectively. The previous two albums were harrowing, theatrical settings of Old Testament scripture and French Decadent poets, respectively, but You Must Be Certain Of The Devil focuses on slightly more conventional songs, many of them rooted in gospel but with original lyrics. The whole thing kicks off with an a cappella version of the spiritual “Swing Low, Sweet Chariot,” sung at the top of her range and presenting a threat to nearby glassware, but “Double-Barrel Prayer” is a pounding industrial dance track that one could almost imagine hearing in clubs, if the DJ wasn’t worried about sending half the patrons streaming out the door. “Let’s Not Chat About Despair” is a punishing diatribe aimed at those who attempted to ignore AIDS. Galás had previously performed her music solo, as powerful a pianist and Hammond organ player as she was a singer, but on Devil she had a guitarist, Kurt Schmidt, on two tracks, and drummer Charlie Terstappen present throughout. On the title track, she delivers a powerful gospel hymn of her own composition at the organ, overdubbing multiple voices so it sounds like she’s not just harmonizing with herself, but fighting with herself. “Malediction” is another rhythm-driven track, on which Galás hectors and haunts the listener as a heavy dance beat pounds away. This was as close to commercially palatable music as she ever got, and it’s still a thoroughly unsettling, even nightmarish journey into the dark.