In the manga, directly after the final scene of "Broly," Goku and Vegeta are tranquilized and conscripted into the Galactic Patrol by Jaco and a mysteriously highly skilled agent named Merus in order to help stop an ancient warlock called Moro, who was only stopped by the Grand Supreme Kai and imprisoned 10 million years ago. With Moro headed to New Namek to use the Namekian Dragon Balls, the two Saiyans travel to the planet and have their first encounter with him, where they are defeated by him using his magic to drain their life essences until near death. Once recovered, they attempt to go after Moro again, but he escapes from them, Merus and the (also conscripted) Majin Buu with the help of his accomplice Cranberry (who he kills) in order to wish upon the Dragon Balls to free all the prisoners in the Galactic Prison. Moro shares his power with the prisoners and absorbs Goku, Vegeta and New Namek's energy while his allies hold the Saiyans off, forcing Goku to teleport himself and everyone else to Galactic Patrol headquarters. After a few days passed, Goku hears from Merus that Moro has grown even stronger and now stand no chance against him. This leads to Goku asking Merus to help train him to master the Ultra Instinct state so he can defeat Moro. Merus agrees and puts Goku through grueling training over the next few days, during which he reveals his knowledge of Ultra Instinct, much to Goku's surprise.