Hiromu Arakawa, award-winning manga creator of the best-selling smash hit Fullmetal Alchemist, draws readers into an intricate new web of magic, intrigue, and life-or-death stakes! In a world where certain humans command mighty supernatural duos called Daemons, it is the birthright of "the children who sunder day and night"--twins Yuru and Asa--to rule over these powerful entities. Separated from a young age and unaware of the truth of their birth, brother and sister must fight to make their way back to each other, claim their birthright, and save the world... Ancient Daemons awaken to fight a new battle in an age-old war!! In a remote mountain village under the watchful eyes of two stone guardians, the young Yuru contentedly lives off the land while staying close to the only family he has left--Asa, his precious twin sister. Asa, meanwhile, carries out a mysterious "duty" on behalf of the village while locked in a cage. Why is Asa a prisoner? And what other secrets does Yuru's otherwise idyllic home hide?