The Bear and the Nightingale by Katherine Arden

This fascinating story based on Russian folklore is the story of Vasya, who can see and speak with the demons who guard the homes and crops.  As the Christian religion takes over, and offerings to the guardians are stopped, there is danger that only Vasya, a wild child who has inherited her ability to communicate with the guardians from her mother's family, can stop - or can she?  The story is intriguing and a fun read!