William Clarence Henry George Ransom is the birth son of Jamie Fraser and Geneva Dunsany. Geneva was married to Ludovic Ramson, the Eighth Earl of Ellesmere, and William is his legal heir.

William was raised by Jamie's close friend, Lord John Grey, who is married to Isabel Dunsany, Geneva's younger sister.

In Outlander Season 7, William, now a soldier in the British army, comes to America to participate in the upcoming Revolutionary War.