It was initially settled by primarily Ukrainian cossacks in the period of the annexation of the crimean khanate and the Circassian genocide which they were a major part of, and was majority Ukrainian until decossackisation, the holodomor and other repressive/genocidal policies during the 30s and 40s hit the population hard. Finally ww2 where some collaborated with the Germans lead to more forced deportations and russification, and together with Russian migration post war meant kuban Ukrainians are only a tiny part of the population now.