The Secret of the Demon Clan in the Apocalypse

A massacre two hundred years ago left humanity with catastrophic casualties. It was carried out to eliminate a group of superhuman people known as demons. In the end, humanity and the gods wiped out the demons under Zeus's leadership, but humanity soon faced retribution: all things began to fall dormant, and resources gradually ran scarce. People started killing one another for resources, and an era of peace gave way to an apocalyptic world filled with ammunition and gunpowder. Then the arrival of a young girl began to change everything.