While serving as an ordinary battle commander during the 2nd invasion, Mazer Rackham managed to destroy the bugger fleet single-handedly.

Spurred by Rackham's success, Interplanetary Fleet undertook a search for a supreme fleet commander to serve during the anticipated 3rd i.nvasion. Rackham "timejumped" fifty years, by spending eight years (subjective) at near-light speed, so as to be available to help train the next commander.

Rackham's successor was Ender Wiggin. Wiggin destroyed the bugger homeworld and was temporarily heralded as the savior of the human race. A generation later, Ender became better known as the destroyer of the bugger race.