See the Enemy.

The North and the South have always been separated by an insurmountable wall. The Barrier — they called it in the North, the Border of Hell — was how the South referred to it. But is it eternal? Yagu from... the island of Iverdade always wanted more than fate offered him, Roy dreamed of glory and the freedom of the Fyon clan, and Innis was searching for her father. Together they embarked on a long journey that led them to the Barrier and collided with the legendary Iron Island. And also — with the Albatrosses of the South: with Rua, eager to bridge the chasm between him and the granddaughter of Horth, and with the Diaz brothers, who lost each other many years ago. A chance encounter and a series of tragic mistakes lead to a rupture of the boundary between worlds. A great war begins.