Reapers

Overview

The Reapers are beings that exist within the Underground realm of The World Ends With You.  The Underground exists in parallel with the Realground, or the world of the living, and is divided into a number of regions that are controlled by the Reapers.  The World Ends With You focuses on the Reapers of Shibuya, a district of Tokyo.
 

The Reapers' Game

As its name suggests, the Reapers' Game is a game that is run by the Reapers.  Recently deceased humans of the Realground are chosen to participate in the Reapers' Game.  The potential reward is high, as the winner is granted a second chance at life.  However, it comes at a steep cost; the entry fee is that which is most precious to the player, and it is only returned if the player wins.  Additionally, those that lose the game lose the right to exist.
 
The Reapers' Game takes place over the course of seven days and is overseen by a single Reaper appointed as the Game Master.  Each day, the Game Master is tasked with presenting the players a challenge that must be completed within a set time limit.  Those that fail to complete the task on time or that fall to the Noise populating the Underground are erased.
 

Organizational Tiers

The Reapers exist in a highly structured organization.  The lowest tier of Reaper is charged with setting and guarding barriers that prevent players from wandering outside the defined boundaries for the day's challenge in the game.  They will only remove the barriers for those that complete tasks they assign to the players.
 
The next step up consists of Harrier Reapers such as Uzuki Yashiro.  Though they are bound to follow the rules of the game, they have more free reign and may challenge the players as they see fit.
 
Above the Harriers are the potential Game Masters.  The Game Master is a role that revolves between a group of especially powerful Reapers.  They define the challenges of the game and can make them as simple or as complicated as they desire.  Game Masters that appear in The World Ends With You include Sho Minamimoto and Mitsuki Konishi.
 
Each district of the Underground is overseen by one Conductor.  The Conductor assigns the task of Game Master and has the authority to dictate how the game is run.  The Conductor is also the one that takes each player's entry fee, and who ultimately determines the game's winner.  The Conductor of Shibuya is Megumi Kitaniji.
 
The Composer is the supreme authority of his or her given district and also has the ability to shape the district.  The coveted position may be taken over by anyone, player or reaper, that manages to kill the current Composer.  The Composer of Shibuya is Joshua.
 
The Producer is an angelic being from the higher plane.  The role of the Producer is to ensure that the rules of the Reaper's Game are being followed, but otherwise does not interfere with the players or reapers.  The Producer of Shibuya is Sanae Hanekoma.