The present study considers exploring monstrosity in Edward Rutherfurd’s sagas The Princes of Ireland (2004) and The Rebels of Ireland (2006). By drawing on J.J. Cohen seven theses on monstrosity, the study approaches two stories in the sagas which represent momentous events in the history of Ireland. First, the study identifies the characteristics of the monstrous, second, it applies them mainly to the conduct of the protagonists of these stories. The study also scrutinises the choice of these characters of their dwelling place to show whether it is randomly made or planned. The strategies of these characters, their diverse practices, and the effect of their monstrosity on others are handled. Finally, in attempting to decide whether their power is driven from internal or external forces the study offers an assessment of the social and political impact of these monstrous characters