X

X may refer to:
 * Mega Man X, the main protagonist of the Mega Man X series. In the Mega Man Zero series he's the true Neo Arcadia leader, known as Original X to distinguish from Copy X.
 * Copy X, the main antagonist of Mega Man Zero. He's a copy of the Original X designed and built by Ciel to be supposedly perfect copy of the original, he's the Neo Arcadia leader in the Mega Man Zero series timeline, taking over Original X's rules.
 * Model X, a Biometal created by Ciel.
 * X (iks), a evil copy of X from Rockman X Mega Mission.