Ivan Bilibin, Baba Yaga, an illustration for a Russian fairy tale (1900s).
Key myth
Helmold of Bosau says the Baltic Slavs toasted a 'black god' and a white one, good and bad. Helmold alone mentions him, and the idea of dualism may reflect a Christian reading.
Where sources differ or caution applies. No Slavic source calls any figure Chernobog; many scholars doubt he existed as described.