Abigail Williams is a fictional character in the mobile game Fate/Grand Order, serving as a Caster-class servant. She is depicted as a young girl with a mysterious and eerie presence, often associated with the Salem witch trials. In the narrative, Abigail is instrumental in unraveling the chaos within the Salem Singularity, where she is portrayed as a conduit for otherworldly forces. Her character embodies themes of innocence intertwined with dark, supernatural elements, making her a unique and pivotal figure in the storyline.