Brainiac 13 first appeared, when the present Brainiac mistakenly brought Brainiac 13 from the 64th century to the present. Brainiac 13 would turn Metropolis into its 64th century version where he ruled it, but was stopped by Superman and Lex Luthor. He would trade Metropolis for Brainiac 2.5 as his last ditch of escape.
He would return to Earth to join forces with Earth's heroes against Imperiex, but his true intentions were to regain control. He was stopped when Superman sent him together with Imperiex Prime's consciousness back 14 billion years to the Big Bang, destroying both villains.