On their first album for Merge Records, The Mountain Goats tackle mysticism and dread the only way they know how: with bright, folky songs and John Darnielle’s inimitable, fervent voice. Taking its name from a made-up deck of tarot cards, All Eternals Deck dips into summery acoustic pop (“Birth of Serpents”), lonely piano ballads (“Outer Scorpion Squadron”), and even a barbershop quartet sing-along (“High Hawk Season”), and underlines all the complex, emotionally loaded lyricism that Darnielle has come to perfect.