The Underworld

Hell is the Afterlife, and the only one. Humanity made no mistakes worthy of this outcome, but God decided he didn't want to share Heaven with humanity, so he closed it off, dooming humans with hell for all eternity.

In hell, Demons watch over and torture the Lost Souls, while the Reaper watches over the Demon as the Warden, and Lucifer watches over the Reaper and makes the major decisions.