The Shinigami Realm
Desolate Afterlife · Gamblers' WastelandThe Shinigami Realm is a barren, decaying world inhabited by gods of death who extend their lives by writing human names. Most of the Shinigami shown are lethargic, bored and more interested in gambling or sleeping than watching the human world. Ryuk drops a Death Note into the human world largely because that stagnation has become unbearable to him.
Why it matters
The entire story begins because the human world looks more interesting to Ryuk than his own.