Saint Seiya: Dark Wing

Shouichirou was just another high school student. Now, he's Wyvern, one of the dreaded Judges of the Underworld, chosen to battle against the forces of Athena in a war that transcends life and death. When an unexpected ambush during a school trip sends Shouichirou and his classmates into the land of the dead, they are thrust into a fierce struggle between the gods and their warriors. The mysterious forces of Hades have already begun their assault, and Shouichirou's destiny is forever altered. But he's not alone—Cattleya, the reincarnation of Athena herself, fights to defend the living, as shocking truths about a darker conspiracy threaten everything they know. (Source: Titan Manga)