Mance Rayder

Mance Rayder is a character in Game of Thrones. Though mentioned in the first season, he is not expected to appear or be cast until a potential third season at the earliest.

Mance Rayder is the King-beyond-the-Wall, a title given to a wildling chief or leader who has unified most of the wildlings under his authority. He has held this position for more than a decade, since Ser Alliser Thorne mentions he was King-beyond-the-Wall during the previous winter.

In the books
In the Song of Ice and Fire novels, Mance Rayder is a former soldier of the Night's Watch. Chafing at the restrictions and orders of the order, he fled over the Wall and took refuge amongst the wildlings. Over several years he became a respected warleader and warrior, and eventually was made King-beyond-the-Wall by acclamation. At the start of the books his name and growing strength has been noted by Lord Eddard Stark, who ponders taking an army beyond the Wall to deal with him before he is summoned south to King's Landing instead.