Fek'lhr

Fek'lhr was a figure in Klingon mythology, a humanoid beast, resembling a feral, monstrous Klingon, who guards the gates of Gre'thor.

In 2367, a con artist claiming herself to be Ardra briefly appeared as Fek'lhr, using holographic technology. 

The was named after Fek'lhr. 

When B'Elanna Torres entered Gre'thor, she was surprised to not see a pit of despair and Fek'lhr torturing the dishonored. 

Background information
The Fek'lhr seen in "Devil's Due" was portrayed by Tom Magee.

Fek'lhr is not considered a deity, because Klingon legend states that they killed their gods. Nor is he considered a devil as Kang said Klingons do not have a devil (Star Trek: The Next Generation Companion). He seems to take the same role as Cerberus from Greek Mythology, Cerberus being a giant demonic dog that guards the gates of Hell.

It is unknown if there is an etymological or mythological relationship between Fek'lhr and the Fek'Ihri, an ancient enemy of Kahless, mentioned by Worf in.

In Star Trek: Armada, Star Trek: Armada II and Star Trek: Starfleet Command III, Fek'lhr is a class of Klingon starship.

In Star Trek Online, the Fek'Ihri strongly resemble Fek'lhr. They are real creatures from outside normal space that attacked the Klingon empire in ancient times, and commanded by Molor during his reign. They have now returned to invade the Empire. It may have inspired the legend. Fek'lhr himself appears as the final enemy of the Fek'Ihri campaign. After scanning Fek'lhr's corpse, the player's Bridge Officers will notice traces of Hur'q technology.

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