Fairy tales
The Grishaverse is full of creatures and people with mysterious powers, some of whom are drawn directly from Russian myth.
The Firebird (Zhar-ptitsa): The myth of the Firebird is seen in many different Russian and Slavic fairy tales and is most often a symbol of rare, magical power. Many of the tales involved people trying to capture the Firebird, especially Prince Ivan, who was the son of the Tsar. In the Shadow and Bone trilogy, the Firebird is the last of Ilya Morozova’s Grisha amplifiers sought by the Sun Summoner Alina Starkov and appears in the third book Ruin and Rising. In both Shadow and Bone and actual folklore, the Firebird has flame-like glowing feathers and eyes like gems.
Baba Yaga: Though Bardugo hasn’t explicitly said the character Baghra is influenced by the tale of Baba Yaga, readers have been pointing out the similarities since shortly after the books were released. In Slavic mythology, Baba Yaga is an ambiguous character, most often described as gruff, elderly, thin and living in a hut standing on chicken legs in the woods. In some stories, Baba Yaga is a terrifying witch who occasionally eats children. In others, she’s a wisened teacher who helps a protagonist on their quest. In Shadow and Bone, Grisha students at the Little Palace aren’t very fond of Baghra’s teaching methods and some are downright scared of her. Bagra clearly holds guarded, ancient wisdom, but takes a liking to Alina (in her own, rough-handed way) and helps guide her on her quest.