Thousands of years ago, the gods in the sky fought against each other in a "Battle of the First Gods". The gods were shattered and turned into countless "spiritual crystals" scattered in the sky world. The spiritual crystals are conceived by heaven and earth, giving birth to "myth cards" - each card seals the remaining will and power of a god, mythical beast or mythical hero. Although the god is dead, his will will always remain in the card, waiting for the holder who is strong enough and compatible enough to be willing to manifest it in the world again.
