Before EEnE Z:Edit
Before his debut in Episode 13, he has, on multiple occasions, attempted world conquest. One of these attempts included controlling Chaos, while another included trying to set free Shadow the Hedgehog. Both of these attempts failed, however.
His last attempt to take over the world, by this timeline, is when he upgraded the real Metal Sonic to take over the world, however; Metal turned on him and tried to rule it himself.
Though Eggman had no hand in the School Wars, Gero and Utonium may have ripped him off somewhat in the creation of their escape pods and Proto-Metal Sonic.
He is first seen with his own breed of Super Saibamen, though they are defeated by the base level heroes after a bit of effort. In Episode 18, he once again returns, this time by sending out three robots of his design, which are also destroyed by the heroes.
In Episode 22's ending, he is working on a project to defeat the Saiyans and the animals, when he recieves a message from "a man thought to be dead" to work on a similar project with him.
In Episode 23, it has been revealed that he has teamed up with Utonium. The two created Mecha Sonic and Mecha Shadow, who have proved themselves loyal(BIG surprise from the former's past). In the end, he and Utonium had an impass and he was launched into the Sun at the end of Episode 34, just before Power Prof. and the newly super-charged Sonic, Shadow and Knuckles engaged in the final battle.