In Klingon religion, the original gods who created the first Klingons were slain by their own creations, because they were "more trouble than they were worth". (DS9: "Homefront") A version of this creation myth is told during the traditional Klingon wedding ceremony: (DS9: "You Are Cordially Invited")
- "With fire and steel did the gods forge the Klingon heart. So fiercely did it beat, so loud was the sound, that the gods cried out, 'On this day we have brought forth the strongest heart in all the heavens. None can stand before it without trembling at its strength.' But then the Klingon heart weakened, its steady rhythm faltered and the gods said, 'Why have you weaken so? We have made you the strongest in all of creation.'
- And the heart said... 'I am alone.'
- And the gods knew that they had erred. So they went back to their forge and brought forth another heart.
- But the second heart beat stronger than the first, and the first was jealous of its power. Fortunately, the second heart was tempered by wisdom.
- 'If we join together, no force can stop us.'
- And when the two hearts began to beat together, they filled the heavens with a terrible sound. For the first time, the gods knew fear. They tried to flee, but it was too late. The Klingon hearts destroyed the gods who created them and turned the heavens to ashes. To this very day, no one can oppose the beating of two Klingon hearts."
One otherworldly creature that remained was Fek'lhr (veqlargh), the guardian of Gre'thor (ghe'tor). The first Klingon, Kortar, was condemned to ferry dishonored warriors to Gre'thor on the Barge of the Dead for the offense of killing the gods (by whom is never made clear). (VOY: "Barge of the Dead")
Most Klingons in the 23rd and 24th century worshipped the legendary hero Kahless the Unforgettable, who was said to await Klingon warriors in the afterlife of Sto-vo-kor. (VOY: "Day of Honor") The worship of Kahless was headed by clerics known as the Followers of Kahless or Guardians. (TNG: "Rightful Heir")