To me, this statement is very vague as he could just be talking about the worlds of the characters we see in the game or it could mean all of shonen jump
The statement is just wrong. Prometheus is never even
suggested to be above the Jump Worlds.
The Real World and the Jump Worlds are neighboring but segregated dimensions, and Prometheus simply acts a middle-man for the two, projecting the events of the Jump Worlds to the people of the Real World in the form of comics.
So, for example, Goku battling and defeating Frieza in his world, and someone robbing a bank in the Real World occurred concurrently. Prometheus then uses the Onyx Book to create a bunch of manga to act as a medium to present the Battle of Namek and various other fights to people in the Real World.
His power does not even come naturally. Everything he does comes from the Onyx Book — a book that has only demonstrated
2-C levels of power.
On top of the whole "Prometheus transcends Shonen Jump" nonsense, some people also like to claim that Prometheus is qualitatively superior to Medaka Kurokami and Najimi Ajimu — two characters who not exist within the game's story or any of the DLC — and the Marvel Universe through the Deadpool manga, which is just inane.
At best, Prometheus, using the Onyx Book, is
2-C for partially merging the Real World with the Jump Worlds — which is why certain stages like New York City or New Mexico have elements of various anime thrown in, like Frieza's Ship or the God Tree from Naruto — and threatening to completely fuse the world's together at the end of the game.