The subject of the article is the semantics, structure and plot functioning of the character system in the Yakut heroic epic. The object of the study is the olonkho "Bogatyr Tong Saar" by Semyon Nikolaevich Karataev, which is one of the exemplary texts of the Vilyuisk epic tradition, recorded during the Vilyuisk expedition of 1938. The relevance of the work is due to the need for a detailed study of the system of characters of the Yakut heroic epic, determining their role in the development of the Olonkho plot, identifying new images. The purpose of the article is to reveal the system of epic characters of the Yakut heroic epic "Bogatyr Tong Saar" by S. N. Karataev. The results obtained can be applied in the field of folklore studies in the development of issues of poetics of an epic text, in the compilation of educational and methodological manuals on Yakut folklore. Structural and functional analysis developed by the famous Russian folklorist V. Ya. Propp is used as the main research method. The novelty of the research lies in the fact that for the first time the system of characters of this legend is studied using the methodology of V. Y. Propp. As a result, it was concluded that the olonkho "Bogatyr Tong Saar" by S. N. Karataev presents a whole system of character images. It was determined that in addition to the characters conditioned by the two parts of the olonkho narrative, images of antagonists – heroes, women-abaasi, rivals play an essential role in the unfolding of the plot. It was revealed that in this text a significant place is occupied by the hero's assistants, the wrecker / kidnapper of the hero's wife (the Tunguska bogatyr). Girls / women are passive, but they play a role in motivating the departure of the hero. In the plot of olonkho, there are images of the parents of the bride / wife, a messenger, an old woman adviser Simekhsin, a victim servant, a blacksmith donor, which are not of great importance in the development of the plot, but complement the main images and contribute to their disclosure.