Mance Rayder

Mance Rayder is the leader of the Free Folk a the start of the game, holding the title of "King-Beyond-the-Wall". Mance is a feared opponent of the Night's Watch, which he formerly served in as a black brother.

Do you know what it takes to unite ninety clans, half of whom want to massacre the other half for one insult or another? They speak seven different languages in my army. The Thenns hate the Hornfoots, the Hornfoots hate the Ice-river clans, everyone hates the cave people. So, you know how I got moon-worshipers and cannibals and giants to march together in the same army?...I told them we were all going to die if we don't get south. 'Cause that's the truth.

―Mance Rayder to Jon Snow

Please see the following links for more info:

https://gameofthrones.fandom.com/wiki/Mance_Rayder

https://awoiaf.westeros.org/index.php/Mance_Rayder