Klingon death ritual
The Klingon death ritual was a Klingon rite performed during, or directly following, the death of a warrior. 

The Ritual involved opening and staring into the eyes of the dying individual, then bellowing loudly at the sky. The former served to observe and confirm the lack of recognition by the dying/dead Klingon's eyes. The latter served as a warning to the dead (presumably in Sto-vo-kor): "Beware, a Klingon warrior is about to arrive".

Once the Ritual was completed, the body was unceremoniously discarded in whatever manner was most convenient. Without the warrior's spirit, the mere body was considered to be "only an empty shell" which should be treated as such. ()

Instances 
It was extremely rare for non-Klingons to witness the Klingon death ritual. ()

The first such case was believed to be in 2257, when L'Rell was called upon to perform the ritual. After Lieutenant  was discovered to be the Klingon sleeper agent Voq, and in danger from having two sets of personalities in his system, L'Rell attempted to heal him by exorcising what remained of Voq's personality from Tyler's mind. Afterward, L'Rell, realizing that Voq was truly gone, performed the death ritual for her old friend. ()

In 2364, Korris, Konmel, and Worf performed the rite, following the death of Kunivas. Soon after, Worf performed the Ritual for Korris, after being forced to kill him when Korris threatened the ship. ()

Worf performed the ritual again in 2367, following the death of his mate, K'Ehleyr, and in 2374 for his wife, Jadzia Dax. Though, in both cases, Worf did not open the eyes of the fallen warrior (each of whom happened to be his betrothed at their respective time of death). In the ritual for Jadzia, he recited the words: neH taH Kronos. Hegh bat'lhqu Hoch nej maH. neH taH Kronos. yay je bat'lh manob Hegh. ("Only Kronos endures. All we can hope for is a glorious death. Only Kronos endures. In death there is victory and honor.") (; )

Worf was last seen performing the ritual in 2375, after slaying Gowron in personal combat. In this instance, Worf opened the slain warrior's eyes. ()

Other Klingon rituals concerning death 
There is a Klingon mummification glyph, indicating that at some point in the past the Klingon mummified their dead. Spock identified this glyph during his mental retraining following his fal-tor-pan. ()

T'Kuvma and his followers followed this practice or one similar to it, preserving the bodies of their dead and placing them in sarcophagi on the surface of the Sarcophagus ship. ()

Ak'voh, the act of watching over a fallen warrior's body, was an ancient Klingon tradition. ()

R'uustai, or "The Bonding", is a rite of brotherhood sometimes performed after the death of an individual's parents. ()

A funeral was held for Dax, son of Kang in 2290. At his young age, it is unclear if Dax completed the Rite of Ascension, becoming a Klingon Warrior. (; )

If an individual dies in a manner that does not ensure entry into Sto-vo-kor, his or her relatives may fight a great battle in the deceased's name; an honorable victory will allow him or her to enter Sto-vo-kor. ()

Appendices

See also 
 Funeral
 Bajoran death chant
 Ferengi death ritual
 Sonchi ceremony
 Mauk-to'Vor
 Hegh'bat
 Transference ritual

Apocrypha 
In Klingon for the Galactic Traveler, the Klingon language translation of "death ritual" is given as "Heghtay".

In The Genesis Wave, Book Two, when two Klingons are vaporised defending Doctor Leah Brahms from her would-be captors while Brahms is leading a Klingon crew in tracing the titular Genesis Wave, her first officer Maltz confirms that the dead died honourably and in a manner that left no body before he joins one of his crewmates in announcing the dead to Sto-vo-kor.

External link 
 

de:Klingonisches Totenritual
Death ceremonies
Klingon ceremonies