Abstract. The primary source of material for this research was the folklore-ethnographic evidence stored in the archives of Karelia and collected over a century-long time period by Karelian folklore researchers. Comparative-historical, synchronous-descriptive and comparative-typological methods were employed. The scientific novelty and relevance of this research arise from the fact that the topic has not been studied through 19-20th century mythological stories of Karelians. The focus of the study was on the images of two mythological characters that are antagonistic and struggle for power over the child: yönitkettäi ‘night placheya (evil night spirit of crying)’ and uniukko ‘old man of sleep’. They enter the house at night, the former by breaking the established taboo, the latter invited by a human. The worlds of the spirits are also antipodal both to each other and to the human world.
Keywords: mythology, folklore, Karelians, night placheya, old man of sleep, beliefs