I haven't been following the MegaMan series since waaaay back, so please forgive me if this is widely known: is there a game in the series that serves as the definitive MegaMan origin story?
Well really, the series isn't built with a storyline like how you're used to it, but the Classic/"Megaman (with no subtitle)" games serve as the basis for everything that goes down in the later games. Thing is, these pretty much boil down to "Wily's fucking our shit up. Light, send Rockboy to fuck his shit up
harder!"
From there, X is the sleeker and faster paced game with some semblance of a plot. Light leaves X as his final work and X is all conflicted because robots are fucking everything up. Eventually he mans up and beats the shit out of the guy responsible for the uprising, gaining a buddy in Zero, Wily's last creation.
Going from X6's implied ending of the X series (couple of centuries after the X series ending -- whenever that is), the Zero series takes place with an amnesiac Zero trying to find out why the last sanctuary on Earth after the past wars is being racist/extremist against robots and killing them off for the sake of maintaining the human population.
Then you get into Mega Man: Power Rangers/Tokubetsu edition with ZX that follows humans gaining powers of the old heroes which has implications on the Legends series and its Megaman who's some kid from Elysium named Trigger/Rock.
Yeah, I was in deep with this back in the day. I kinda sparknote'd some stuff, but it's a guilty pleasure of mine, I enjoy the lore behind the games. I think it's because I like the character of Megaman/X.