One faction in the Russian Civil War

"Black Guards

Black Guards (Russian: Чёрная Гвардия, 'Chёrnaya Gvardiya') were armed groups of workers formed after the Russian Revolution and before the Third Russian Revolution. They were the main strike force of the anarchists. They were created in the autumn of 1917 in Ukraine by Maria Nikiforova and in January 1918 in Moscow, under the control of anarchists at industrial enterprises by Factory and Plant Committees and by Moscow Federation of Anarchist Groups cells. In the beginning of 1918, in reaction to the growing repression of all opposition and free expression, the anarchist groups within the Moscow Federation formed armed detachments, the Black Guards headed by Lev Chernyi. The Black Guards were the basis for the later formation of the Black Army. Hence, the term is often used as an English synonym for the Black Army when referring to the era of the Third Russian Revolution and Russian Civil War.

The Treaty of Brest-Litovsk and deprivations of the Civil War provoked dissensions among the left, which were suppressed by the Bolsheviks. On the night of April 12, 1918 the Cheka (secret police) raided the 26 anarchist centres in Moscow, including The House of Anarchy, the building of the Moscow Federation, and the Black Guards offered armed resistance. A fierce battle raged on Malaia Dimitrovka Street in which about 40 anarchists were killed or wounded and about 500 were imprisoned. Some former Black Guards took part in the Left SR uprising on July 6, 1918."
http://en.wikipedia.org/wiki/Black_Guards

"Nestor Makhno and the Insurrectionary Anarchist Army

Ukrainian anarchist guerrilla bands were active during the Russian Civil War. Some claimed to be loyal to the Ukrainian state, but others acknowledged no allegiance; all fought both Red and White Russians with equal ferocity in the opening stages of the Civil War. Of all the anarchist groups, the most famous and successful was that of the peasant anarchist leader Nestor Makhno, aka Batko ("Father"), who began operations in the southeastern Ukraine against the Hetmanate regime in July 1918. In September, he formed the Revolutionary Insurrectionary Army of Ukraine, or Anarchist Black Army, with arms and equipment largely obtained from retreating Austro-Hungarian and German forces. During the Civil War, the Black Army numbered between 15,000 and 110,000 men and was organized on conventional lines, with infantry, cavalry, and artillery units; artillery batteries were attached to each infantry brigade. Makhno's cavalry incorporated both regular and irregular horse-mounted (guerrilla) forces, and was considered among the best-trained and most capable of any of the cavalry units deployed by any side in the Russian Civil War. "
http://en.wikipedia.org/wiki/Revolutionary_Insurrectionary_Army_of_Ukraine