The Kurta Clan was the clan that Kurapika belonged to until the whole clan was wiped out by the Phantom's Troupe.
The clan's peoples' eyes were brown in a normal state. But if they get excited, their eyes would change colour to a beautiful scarlet red. Due to this specialty, their eyes were listed as A-class treasures, extremely wanted by treasure collectors.
The whole clan (except Kurapika) was murdered by the Phantom's Troupe because the troupe's leader Chrollo Lucilfer liked their scarlet eyes and wanted them, and the troupe obtained them forcibly by killing them and taking out their eyeballs. Kurapika was the only survivor.