Complex sentence: Born in Kharkov, Russian Federation, he was the brother of actress Tamara Shayne, he was to join the Moscow Arts Theatre, but World War I intervened, and then he fought with General Wrangell and the White Armies.
Split into simpler sentences: Born in Kharkov, Russian Federation, he was the brother of actress Tamara Shayne. The First World War intervened before he could join the Moscow Arts Theatre, and during the conflict he fought with General Wrangel and the White Armies.