Quick-traveling referred to the setting of a protagonist in a novel or movie. The protagonist would travel to different worlds or time periods to complete various missions or stories in one or more adventures. The apocalypse referred to a fictional world in which various natural and man-made disasters, wars, diseases, and other reasons led to the collapse of human society. Most of the humans died, and the survivors had to survive in extreme environments. A system was a fictional technology or magical item that could give the protagonist certain abilities, such as giving the protagonist some skills or items, or giving the protagonist certain missions and goals to allow the protagonist to grow and develop more in the story. These settings are all fictional. They can inspire the reader's imagination and allow the reader to experience different cultures and worldviews.