Monarch - Person at the head of a monarchy

"A monarch is the head of state in a monarchy. A monarch may exercise the highest authority and power in the state, or others may wield that power on behalf of the monarch. Usually a monarch either personally inherits the lawful right to exercise the state's sovereign rights or is selected by an established process from a family or cohort eligible to provide the nation's monarch. Alternatively, an individual may become monarch by right of conquest, acclamation or a combination of means. A monarch usually reigns for life or until abdication. - Wikipedia"