Earth was in dire need of a hero from beyond the system of Angels, Devils, and Monsters. Someone who was not afraid to stand up for humanity at all costs. This hero was Zero. A man from beyond the universe. Hero? I quit a long time ago / Highschool DXD crossover.

Goku meets an old enemy that warns him of coming doom and tells him he is the only one that can save the omniverse. While this is true, Goku can't help but think that that's not all the Demon Lord has in mind. Join the unlikkely alliance of Goku and Demigra as the two travel the Omniverse in an attempt to stop the coming doom.