Underworld (n.) is at an equal distance from all places, so it matters nothing where one dies.
4 definitions
Definition.com
Definition.com
The Underworld (n.) is where one is united with everything once dear, yet cannot enjoy the reunion, because it is all shadowy and unreal.
Definition.com
Underworld (n.) was invented by men who could not conceive a soul without a body: they could see nothing by their mind alone, so they referred all to their eyes.
Definition.com
The Underworld (n.) is, in primitive belief, the land of dreams; and the unconscious, which dreams come from, does seem relatively free of space and time.