Gestalt, Vol. 1 by Yun Kouga

[Viz] The quest for a man's soul, the battle for his heart, the war for a world. In the legendary past the gods battled for supremacy and cast out the demon god whose name cannot be spoken. Banished to Earth, the demon found refuge on the mysterious and dangerous island known only as "G." In the legendary past the gods battled for supremacy and cast out the demon god whose name cannot be spoken. Banished to Earth, the demon found refuge on the mysterious and dangerous island known only as "G." After experiencing a crisis of faith, Father Olivier of the Valaria Order decides to go to G and find out the truth behind the legends. Olivier's journey is unsanctioned, and the head of the Order engages the dark elf Suzu to stop him. As he begins his quest, Olivier encounters Ouri, a young girl from the south who cannot speak. But Ouri reveals another side of herself when Suzu catches up to them!