The Seven Deadly Sins: Four Knights of the Apocalypse 17

In the forest of fairies, Percival lies in a deep slumber. Nasiens works tirelessly, holding on to the hope of his recovery, while the forest's inhabitants watch over him with warmth and support. But one among them, Mertyl—the son of the Fairy King and Giant Queen—feels his heart stir with growing doubt. Manipulated by an outside force, Mertyl is consumed by suspicion, distrust, and a crushing sense of inferiority. As despair and anger take hold, he turns against Nasiens and even his own family. When this lonely soul falls into darkness, the fragile peace of the forest is shattered, and the air grows heavy with the promise of a great tragedy…

Volume 17 of The Seven Deadly Sins: Four Knights of the Apocalypse manga series by Nakaba Suzuki.