Viktor Fedorovych Bilash was the Chief of Staff of the Revolutionary Insurgent Army of Ukraine (RIAU) under Nestor Makhno. A gifted military commander, Bilash himself planned many of the Insurgent Army's operations, later becoming its commander in chief after Makhno's flight into exile.

The Revolutionary Insurgent Army of Ukraine, also known as Makhnovtsi, named after their leader Nestor Makhno, was an anarchist army formed largely of Ukrainian peasants and workers during the Russian Civil War of 1917–1922. They protected the operation of "free soviets" and libertarian communes by the Makhnovshchina, an attempt to form a stateless anarcho-communist society from 1918 to 1921 during the Ukrainian War of Independence.