Giygas

Giygas is the main antagonist of every game in the Mother series except for Mother 3.

EarthBound
In EarthBound, he has ruled the world ten years into the future, until Ness beats him, hearing about him from Buzz Buzz. Ness goes through all of Eagleland to find and defeat Giygas, gaining three companions along the way. Giygas must be fought in the past, and to go there, the Phase Distorters must be used. The third one brings the party to him, with them becoming robots in the process. When finally defeated, the game will end.