The Fifth One (mainly referred to just as The One at the time) was a legendary human male born inside the Matrix who somehow became powerful enough to manipulate nearly any aspect of the Matrix to his liking. Referred to as "The Anomaly" by the Machines, he was mysteriously exempt from the rules of the system and was literally capable of altering it's structural integrity. Later, Neo realizes that he is indeed the new One. Upon hearing the news, Zion rejoiced as Neo began to accept his role as their savior.