Mance Rayder is a character featured in A Song of Ice and Fire and Game of Thrones. He is a former member of the Night's Watch who defected to the Free Folk (AKA the wildlings), his real people, eventually rising to become their leader, officially styling himself as the King-Beyond-the-Wall.
In the television series, Mance is portrayed by Ciarán Hinds and serves as one of the main antagonists of the Night's Watch storyline during Seasons 2, 3, and 4 (despite not being seen in Season 2.)
Though he is considered a villain because he is a major enemy of the Night's Watch, Mance is not inherently evil and is more of an Anti-Villain, because he genuinely cares for the well-being of his people and has many honorable qualities.