Riff Tamson is the main antagonist of the Mon Calamari arc of Season 4 in Star Wars: The Clone Wars.
He is a member of the Confederacy of Independent Systems, serving as a warlord in the Separatist Military and the commander of the Separatist forces stationed in Mon Calamari during the battle for the planet. There, he was secretly responsible for increasing tensions between the Quarren and the Mon Calamari, which resulted in a civil war between the two races. He is Lee-Char's arch-nemesis.