The Lornak entered a violent feud with the Tralesta clan in 2086. It lasted 200 years until 2286 when the Lornak conducted a massive campaign against the Tralesta, called the Tralesta Massacre. It eradicated its members, killing all but five members.
The Lornak's numbers dwindled afterwards, mostly due to the surviving Tralestas' plan. Yuta, the chosen surviving Tralesta from the massacre, made it her mission in life to kill all of the Lornak. She nearly accomplished this in 2366 when she attacked Chorgan, the last living member of the Lornak clan at the time, during negotiations between him and Sovereign Marouk. (TNG: "The Vengeance Factor", okudagram)