Mega Man

In the fictional universe of Mega Man, the classic Mega Man series consists of 11 main titles including the original game, as well as all Game Boy and PC titles featuring the original design of Mega Man/Rockman. The classic series is considered to be the origin of the story, with Mega Man being the first installment, and continuing with the direct sequels Mega Man 2-10 games. Chronologically after 8 comes Mega Man and Bass, and then comes Mega Man 9, then Mega Man 10.
There are also spinoff titles that do not relate to the series' storyline. The continuity of the Game Boy games' plots, as they relate to the main storyline, has never been confirmed officially. Although the classic series has yet to reach an ending, the storyline shifts to the Mega Man X series, followed by Mega Man Zero and finally Mega Man ZX. Although it is said that the Mega Man Legends series takes place sometime after the ZX series, there is an uncertain amount of time as to when it actually takes place. Mega Man Battle Network exists as an alternate universe or timeline. The Japanese language source book outlines the Classic, X, and Legends series and makes mention of the Battle Network and Zero series (which were fairly new at the time of the book's publication.) While the ZX and Star Force series were not yet conceived when the source book was published, Capcom explicitly states their placement in the timelines within the games themselves. Mega Man Star Force follows the Battle Network series