Babylon, the medieval city of the spirit realm, was destroyed by whom they called the Genesis, a group of explorers who searched for its existence. Led by scientist Ogai Yamada, they searched into the realm to retrieve what is called the Stone of Life, a precious stone that brings spirits back to life. But after all their efforts looking for it, the Guardians of Babylon prevented them from entering, demanding them to leave.
In response, Genesis unleashed a lethal attack on them, destroying everything in its path: homes, farms, villages, killing men, women, and children. This left Lieutenant Mizore Hidero to order his men to halt after seeing the murderous act of Ogai Yamada.
Mizore was court-martialed for his actions and sentenced to life imprisonment with his platoon ordered by their Emperor to commit sacrificial suicide for desertion in the midst of battle. Mizore was never the same and killed himself afterwards.