Mega Man lore is absolutely fucking wild if you really parse through it realize just how much Dr. Wily is indirectly responsible for causing.
Wily is responsible for creating Zero and the Zero Virus that went on to transform Sigma indirectly. The same Zero and Virus that went on to shape the future for the worse, as they were major factors in both the Maverick Wars and Elf Wars.
Sigma became infected with the Zero Virus that evolved into the Sigma Virus and turned Sigma Maverick in the first place. Which would lead to 8+ Maverick Wars which includes him being responsible for attempting to drop the entirety of the Space Colony, Eurasia, onto the planet, which even in the Good Endings where it's blown up still causes long term environmental damage for years to come (until 100 years later where it's crash sight, Area Zero, had the nature around it began to regrow due to an environmental control system that survived the crash), just to try and awaken Zero's potential by factory resetting him and making him the villain Wily intended during the fifth Maverick War.
Dr. Weil meanwhile is the one who corrupted the Mother Elf made by analyzing Zero's body in order to find a cure to the Sigma Virus, and then used Zero's original body as the vessel for Omega which kicked off the Elf Wars, an event that resulted in over 90% of all life, human and Reploid alike to be extinguished and later attempts to destroy Area Zero with the orbital space laser, Ragnarok which even after his death at the end of the Zero series, Weil's soul and hatred haunts it's remnants as the Model W for the duration of the ZX series.
To put that into perspective. Sigma is responsible for the devastation of Earth and causing long term damage to nature for hundreds of years. Dr. Weil is responsible for the war that caused countless lives, both organic and mechanical alike, to be lost. Dr. Wily's final creations are indirectly the foundation for massive future events, his actions haunt the future by helping make the other two big bads become as dangerous as they did.
Hell it's even implied Wily still lived on and haunts the events of Mega Man X as Serges and Isoc are implied to be Reploid bodies for Wily, and X5 even has Sigma mention an old man who knows a lot about Zero and has built quite a few robots.
It's both really interesting and really terrifying to think about just how much overall importance Wily has to the Mega Man universe. If Zero and the Virus did not exist, the Mavericks would not have gotten as bad as they became in canon once the Maverick Virus became a thing, and there would be no Mother Elf created to combat a virus that didn't exist and later be corrupted. If you remove Zero and the Virus from the Mega Man Mythos... You can't have the story of Mega Man X onwards.
It's also hilarious to realize how much Sigma and Weil's greatest feats and failures from off the doctor's work through the Maverick Virus and Zero's body respectively only for Zero himself to be a major player in their defeats regardless. For ironically not only was it Wily's own designs that caused them both to not only rise to power, but it also those same designs that caused them to later fall as well.
