Katherine Arden
1) Dark waters
Author
Description
Friends Ollie, Coco, and Brian discover their nemesis, the Smiling Man, is back when the group goes sailing on Lake Champlain with their parents and Brian's former best friend Phil, and their boat becomes shipwrecked on a mist-covered island. Hunted by snakelike creatures, the group will have to find a way around the Smiling Man's tricks to escape the island alive.
Author
Description
Vasilisa's gift for seeing what others do not won her the attention of Morozko-- Frost, the winter demon. But Frost's aid comes at a cost, and her people have condemned her as a witch. Driven from her home, she faces an impossible choice: marriage or life in a convent. Instead she dresses herself as a boy and sets off astride her stallion Solovey. Prevailing in a skirmish with bandits, the Grand Prince of Moscow anoints her a hero for her exploits....