is a japanese manga series by yoshihiro togashi. the series tells the story of yusuke urameshi. he died saving a child from a car. yusuke goes through tests presented by koenma, the son of the ruler of the afterlife underworld. after those tests, yusuke is brought back to life. he then becomes "underworld detective" and investigate many cases involving demons and ghosts in the human world. later manga becomes more focused on martial arts battles and tournaments. togashi began creating the series in november 1990.