The Underworld is a vital location in Maximo: Ghosts to Glory. Grim is the only individual implied to have jurisdiction over its inhabitants, and it is where it apparently is his job to send the dead. This may imply that he is the employee of a higher being who has some interest in having the dead preside there. It is explained that this is where human souls are harvested from in order to create Achille's undead army. It is also a stage in which Maximo must enter to rescue a friend later in the game.