Isekai is a subgenre of Japanese fantasy and science fiction that revolves around a person or people who are transported to and have to survive in another world. In the new world, the person usually gains formidable powers or some other importance that they did not have in the previous world. The transition between worlds may occur through death and reincarnation, through summoning by an object, god or person in the alternate world. A common setting is a medieval-like world populated with humans, humanoids, and monsters. In a reverse isekai, a person from another world is transported to planet Earth.