Two thousand years ago, countless meteorites fell to Earth. Animals and plants began to mutate, and energy returned to the world. People called the resulting creatures aberrations or card beasts, and humanity was gradually pushed toward extinction. Later, people discovered that cultivation could make them stronger. At the same time, cards appeared. People found that cards could help them fight the aberrations, and that they could form summoning contracts with the creatures inside them. Humans helped the card creatures grow stronger, while the creatures helped humans fight back, though the contracts carried risks. Some creatures hated forming contracts with humans, and some even killed their summoners. Those who successfully summoned a creature and fought alongside it were known as Card Summoners. Those without a card creature to aid them were called Hunters.
