Lukara was a Klingon woman who lived in ancient times, the great love of Kahless the Unforgettable. Kahless and the Lady Lukara were in the Great Hall of Qam-Chee when it was stormed by five hundred of Molor's troops. The city's garrison fled, but the two of them fought off the intruders alone, and thus began "the greatest romance in Klingon history." The same night they "jumped on each other like a pair of crazed voles." (DS9: "Looking for par'Mach in All the Wrong Places")
This character was only mentioned in dialogue.
In DS9: "Looking for par'Mach in All the Wrong Places", taking place in 2373, Worf enthusiastically mentioned the events in Qam-Chee to have happened "a thousand years ago." This would appear to be somewhat of a contradiction as TNG: "Rightful Heir" and TNG: "Firstborn" both state that Lukara and Kahless lived 500 years earlier. Either Worf "rounded" the number of years in his enthusiasm, or Molor and Kahless were at least 500 years old, which while the maximum life span for Klingons has never been clearly defined, seems to be without precedent. Another solution would be that Worf counted in Klingon years, as 2373 corresponds to the Year of Kahless 999.