The Whitby Witches: A Warlock In Whitby by Robin Jarvis
This gripping series relates the adventures of two orphans, Jennet and Ben. Living in the town of Whitby, they become embroiled in the lives of the fisherfolk - strange creatures whose existence is under threat from deadly enemies ...A WARLOCK IN WHITBY introduces Nathaniel Crozier "the most evil man on Earth" and the fish demon, both of whom pose a terrible threat to Whitby and the fisher folk