In Finland, independence was sealed after a savage civil war where the real divisions were not ethnic or religious but along class lines.

From The Long Shadow: The Legacies of the Great War in the Twentieth Century by David Reynolds.  Page 12.

Elsewhere on the Russian borderlands state building was equally violent. Ukraine enjoyed a brief taste of freedom before most of it was absorbed into the new Soviet Union. The Baltic states did hang on to independence, albeit after bloody struggles in 1919–20 against various Russian armies. In Finland, formerly a grand duchy enjoying autonomy in the Tsarist Empire, independence was sealed after a savage civil war in the first half of 1918 where the real divisions were not ethnic or religious but along class lines. This pitted the Reds, backed by Bolshevik Russia, against the Whites, aided by Imperial Germany. Terror was ubiquitous and mutual animosity endured for decades after the White victory. Survivors from each side lived in almost separate communities, with their own newspapers, entertainments, and sports clubs.