jamadhar
Jamadhar is a weapon of Indian origin, looking somewhat like a mixture of brass knuckles and a dagger.
Also known as katar or katara. Japanese Wikipedia article on jamadhar states that "the western naming convention of Indian push daggers as katar, kutar or katara is actually a misapplication of the word, as katar properly refered to a type of double-edged short sword. This misinterpretation arose from the illustrations of the katar and jamadhar being reversed in 'Ain-i-Akbari' a 16th century historical account authored by Abu'l-Fazl, who served Emperor Akbar of the Mughal Empire."
Famously worn by the Assassin class in Ragnarok Online and Diablo 2, and by Voldo in the Soulcalibur series (who dual wields a triple-bladed variant).