Russian Empire was allied with the Serbians, who were considered fellow Slavs.
Germans/Austrians were not keen on fighting on the eastern front with the powerful Russian empire and thus wanted to destabilize the country making it incapable of fighting against them (which they actually succeeded: the Soviets signed a humiliating treaty ending the war on the eastern front while ceding huge territories to Germany/Austria). Thus, they assisted the revolutionaries, among them Trotsky and Lenin.
Russian Empire was allied with the Serbians, who were considered fellow Slavs.
Germans/Austrians were not keen on fighting on the eastern front with the powerful Russian empire and thus wanted to destabilize the country making it incapable of fighting against them (which they actually succeeded: the Soviets signed a humiliating treaty ending the war on the eastern front while ceding huge territories to Germany/Austria). Thus, they assisted the revolutionaries, among them Trotsky and Lenin.