The Human World is Earth. Earth within the Death Note universe is identical to that of "real life" in both appearance and life forms. Every aspect of the Death Note universe (excluding Death Notes and Shinigami) is intended to mirror that of "real life."
The Human World is dominated by humans in a similar fashion to the Shinigami Realm being dominated by Shinigami. One unique aspect of the Human World in the series is its seemingly one-way connection to the Shinigami Realm. Humans are never shown to enter this realm, and no access point is ever mentioned or shown to exist in the Human World. Shinigami, however, can travel to the Human World, and they watch humans through spherical observation holes found throughout the Shinigami Realm.
- Main article: Humans
Humans within the story are biologically identical to humans in "real life." Any change made to a human through the Death Note is considered to be a supernatural event. Humans who gain Shinigami Eyes have their lifespan shortened through supernatural events, not through a change in their biological makeup. Humans who are affected by a Death Note (i.e. their name is written in it) will die if the name is written under the Rules of the Death Note. This will happen regardless of the previous health of the victim (i.e. a healthy person will die if their name is written in the Death Note).
Japan is the primary setting of the Death Note series, and as such, many important events take place in this location. It is the home of Light Yagami and the location that the Shinigami Ryuk drops his Death Note.
Within Japan, important locations include:
- The headquarters of the Japanese Task Force
- The Yagami family's house
- Sakura TV Station
- Yotsuba headquarters
- Yellow Box Warehouse
The United States of America (USA)
The United States (U.S.) plays an important role in the series beginning with L's use of FBI agents in the Kira investigation. The U.S. later creates the SPK, an investigation team hunting Kira that is headed by Near and consists of FBI and CIA agents. The U.S. is also home to what is known only as the Mafia, a criminal organization under the strong influence of Mello.
Within the United States, important locations include:
- The Mafia's various hideouts
- The White House
England is seen only once in the series. It is notable, however, as the location of Wammy's House, a small orphanage founded by Quillish Wammy (aka Watari). The orphanage is located specifically in Winchester. Wammy's House is known for housing children of outstanding abilities and talent and was the former home of L, Near, Mello, and Matt.
For more information on Winchester, England, see: Winchester.
Within England, important locations include:
- Wammy's House
All organizations that exist in "real life" are assumed to exist within the Death Note universe. Many of these organizations have roles within the storyline. These organizations are:
- The United Nations
- The International Criminal Police Organization (ICPO or Interpol)
- The National Police Agency (NPA)
- The Japanese Police Force
- The Federal Bureau of Investigation (FBI)
- The Central Intelligence Agency (CIA)
- The Mafia
There are also organizations that exist solely within the Death Note universe. These organizations are: