Mary Katherine Blackwood

Mary Katherine Blackwood is the main character in Shirley Jackson's 1962 novel, We Have Always Lived in the Castle. The eighteen-year-old "Merricat" lives with her remaining family members, Constance and Julian Blackwood, on an estate in Vermont. As a result of a tragedy six years prior the family remains isolated from the surrounding village.

The Dictionary of Literary Characters designates a "definition" to Merricat as follows: Reclusive, psychotic 18-year-old who lives in the family manse with her older sister, Constance Blackwood, and her uncle, Julian Blackwood, as a child, poisoned most of her family in Shirley Jackson's We Have Always Lived in the Castle.She practices sympathetic magic in order to keep her family out of harm's way. Extremely superstitious, she exudes mysterious behavior and further shows signs of psychopathy and obsessive–compulsive disorder as her role expands.