The relationships between the main characters in "How Steel Was Tempered" were as follows: The protagonist grew up in a family of steel workers in the Soviet Union. He became a brave and strong soldier in the revolutionary war and later became an excellent steel worker and a commoner. 2 Daya Alekseyevich Ostrovsky (Daya Alekseyevich Ostrovsky): The protagonist's mentor and close friend played an important role in How Steel was Tempered, providing a lot of help to the protagonist's growth and revolutionary struggle experience. 3 Zhu Helai (Zhu Helai): The Soviet leader played an important role in How Steel was Tempered. He was the supporter and practitioner of the revolutionary struggle of the protagonists, such as Kochagin and Ostrovsky. 4 Yeremenko (Yeremenko): Kochagin's classmate and friend in "How Steel Was Tempered" is a strong character, brave and kind character, providing a lot of inspiration for the growth of the protagonist. 5 Nikolay Nikolayevich Timur (Nikolay Nikolayevich Timur): A soldier of the Soviet Red Army, a good friend and supporter of Kochagin and Ostrovsky, played a very important role in How Steel Was Tempered. These relationships were a very important part of How Steel Was Tempered. They formed the main clues of the novel's plot, showing the growth of the protagonist, Kochagin, and others, their experience in revolutionary struggles, and the complexity of human nature.