The world after the death of elves

Introduction: A new book has been released, and there are another 200 million words of "Elves Are Coming to the World" available for tasting. ...Why is there no elves in this world, only souls? Are all elves dead? Why is it that everyone’s dream is to become a spirit master instead of a trainer, so that the soul can use the power of spirits by communicating with the soul? Can anyone tell me where this is...where have all my elves gone? My dream is to become an elf master! I want to go home!