Chrono Crusade, Volume 4 - Devil to Play

Set in the 1920s, Sister Rosette, an exorcist for the Magdalene Order, and Chrono, the devil with whom she has a contract, exterminate monsters and devils. All the while, Rosette searches for clues that will lead her to her younger brother, Joshua, who was taken away by the devil, Aion. Along the way, they meet Azmaria, a young singer with a powerful gift from God, and Satella, a jewel summoner who truly despises devils for a personal reason. The four of them continue their travels and missions until Aion ups the stakes and attempts to end the world.