Fek'lhri

The Fek'lhri were a race of demons within Klingon beliefs. 

During the time of Kahless the Unforgettable, the legendary warrior forged the first Bat'leth which he used to conquer the Fek'lhri. 


 * Considering the name, its possible that there exists a relationship between them and the Fek'lhr but the nature of it is unknown.