Star Trek: 10 Ways The Klingons Have Developed Since The 1960s
2. Or Gre'Thor?
As depicted in the Star Trek: Voyager episode Barge of the Dead, Gre'Thor was the afterlife for Klingons who died without honor.
It was the exact opposite of Sto-vo-kor. Instead of being greeted by the spirit of Kahless the Unforgettable, the dishonored dead were met by Fek'lhr, the gnarly-headed bestial Klingon thing first seen in the Star Trek: The Next Generation episode, The Devil's Due. Rather than eternal feasting and combat, Fek'lhr meted out eternal torments, much like the Devil in some versions of Christian Hell.
However, the torments of the dishonored dead began long before they even arrived at Gre'Thor's gates. After they died, the dishonored dead were ferried down the River of Blood on the Barge of the Dead. The barge was captained by Kortar, the first Klingon.
While on the barge, the dead were tempted by siren-like serpents, the Kos'Karri. These serpents called to the dead in the voices of loved ones before dragging them into the water to spend eternity. For example, in Barge of the Dead, B'Elanna Torres heard the voices of her Voyager crew mates.