The Mega Man X games, known as Rockman X in Japan, is a spin-off of the popular Capcom franchise "Mega Man" (Rock Man in Japan). The main character is X, a taller, more armored version of the familiar Mega Man. Debuting on the SNES, the Mega Man X games were meant to be cooler, more action-packed games. Since then, they have expanded into being the main Mega Man series.
This series is also the debut of the fan-favorite Zero, who starts off as an enemy. Other characters were introduced, such as Axl, to lesser fanfare.