Tralesta
From Memory Alpha, the free Star Trek reference.
In 2286, the Tralestas were all but wiped out in a massacre engineered by the clan's blood enemies, the Lornak. After this massacre, only five Tralestas were known to be alive. One of these, a woman named Yuta underwent a biological alternation which slowed down her metabolic functions, thus allowing her to age at a much slower rate. Throughout the next century, Yuta exacted her revenge by tracking down and killing all but one of the Lornaks with a genetically engineered microvirus.
The Tralesta clan was exterminated when Commander Riker was forced to kill Yuta after she attempted to kill the last remaining Lornak, Chorgan, during negotiations between him and Sovereign Marouk. (TNG: "The Vengeance Factor")
