Who could have guessed that a band called The Civil Wars would end in acrimony? The duo of John Paul White and Joy Williams enjoyed a storybook arc. Arranged together by chance at a songwriters workshop, their twin voices seem cleaved from a single source, and their rare blend of artistic and commercial appeal — grit and shine, "Poison & Wine" — positioned them in a darling triangle with T Bone Burnett, Taylor Swift and Adele, each of whom contributed in some way to the group's bright, brief rise. After two albums, four Grammys and one canceled tour, the treaty came in the form of tersely worded press releases in 2014 thanking the other for their time. Williams responded by shedding her skin, issuing an eclectic, bombastic synth-pop LP, Venus, in 2015. White has largely stayed inside his Southern Gothic cocoon, cofounding Single Lock Records in 2013 and collaborating with a wide swath of its artists, from 26-year-old Dylan LeBlanc to 74-year-old Donnie Fritts. White's latest solo recording, August's Beulah, is his first since The Civil Wars-preceding The Long Goodbye, another singer/songwriter showcase starring a martyr who somehow survived the war. "I've been over this before," he sings, now joined by The Secret Sisters, two more members of the Muscle Shoals family. "Won't get over it again." The Kernal opens. Tickets $15 in advance, $18 day of show.