Athanasios Klaras (Greek: ??a??s??? ????a?, August 27, 1905 – June 16, 1945), better known by the nom de guerre Aris Velouchiotis (Greek: ???? ?e??????t??), was the most prominent leader and chief instigator of the Greek People's Liberation Army (ELAS), the military branch of the National Liberation Front (EAM), which was the major resistance organization in occupied Greece from 1942 to 1945.