They call him Mance Raider?
Do they mean Mance Rayder? Does the nickname predate Game of Thrones?
“Mance Rayder
“Mance Rayder is a former member of the Night’s Watch who later deserted. Since then, he has become known as King-beyond-the-Wall. In A Storm of Swords, he unites all the wildlings under his command and leads them to attack the Wall from the south trying to guide his people to safety from the advancing White Walkers. His vanguard is defeated by Jon Snow at the Wall. During a parlay with Jon, Stannis Baratheon and his army rout the wildlings, and Mance is taken prisoner. Stannis orders Mance to be burned alive in A Dance with Dragons, but Jon later discovers that the priestess Melisandre used magic to disguise Rayder as the wildling who was burned in his place, escaping execution. Jon orders Mance to rescue Arya Stark, not knowing the girl is actually Jeyne Poole. In Winterfell, the party secretly kills off several of Roose Bolton’s men, creating tension in Winterfell, and enlists the help of Theon Greyjoy to smuggle Jeyne out of the castle, but Mance is forced to stay behind. Ramsay Bolton later sends a letter to Jon claiming that he has captured Mance and is holding him prisoner.
“In the HBO television adaptation, he is portrayed by Ciarán Hinds. In the show, Mance Rayder is not saved by Melisandre and his execution is genuine.”
https://en.wikipedia.org/wiki/List_of_A_Song_of_Ice_and_Fire_characters#Night’s_Watch_and_wildlings