Sergei Ivanovych is Constantine’s half-brother. He is intelligent and has a philosophical mind. Working as a writer, he prepares a big book about the history of Russia and its current political state. When he finally publishes it, but nobody finds interest, he changes the topic trying to adapt to the society. Levin and Sergei have lots of interesting conversations, but the latter man is more talking about abstract notions while the former is interested in practical things. Although he has feelings for the woman Varvara, he cannot build a relationship because of his cold attitude to life. He cannot relax and gain the satisfaction of the surrounding world.
Sergei Koznyshev in the Essays