WARNING: The following contains spoilers for Dragon Ball Super Chapter 63, by Akira Toriyama, Toyotarou, Caleb Cook and Brandon Bovia, available now in English from Viz Media.

In Dragon Ball Super Chapter 42, Goku revealed to Vegeta that he hadn't been able to tap into Ultra Instinct since his battle with Jiren during the "Universe Survival Saga." However, after losing to Moro on New Namek, Goku went away to train with Merus -- an Angel disguised as a Galactic Patrolman -- so as to learn the powerful transformation. While Goku did indeed showcase his new Ultra Instinct transformation against Moro when the hero returned to Earth, he hadn't quite mastered the form properly. Instead, Goku had only learning Ultra Instinct Sign, which is a sort of entry-level version of the transformation. Although this transformation was strong, the power drained caused by Ultra Instinct Sign resulted in Goku failing to beat Moro, who promptly defeated the Z-Fighters.

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However, Merus then returned to Earth to save his friends and the Earth from destruction. Now, the latest chapter of Dragon Ball Super reveals Merus returned with the intention of helping Goku unlock Ultra Instinct's full power.

At the start of Dragon Ball Super Chapter 63, Merus teleports Goku and the Z-Fighters away so that they can be healed by Dende. Moro and Merus battle, but it quickly becomes apparent the latter is just buying time until Goku returns. When Goku does finally rejoin the battle, Ultra Instinct Sign still proves too weak against Moro. "Dammit... you spent all that time teaching me Ultra Instinct," Goku laments, "And I still can't get the hang of it."

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In response, Merus tell Goku that the training did work, and that "one last push should trigger it." The two are then interrupted by Moro, who attempts to copy Merus' ability. However, the Angel destroys the jewels through and in which Moro stores his various copies of abilities, taking away the villain's most powerful new ability. Still, as Angels are supposed to be impartial, Merus fades more and more from existence with every attack.

After shattering the jewel in Moro's forehead, Merus explains to Goku that the reason he's sacrificing himself is that, while he's supposed to remain impartial, he can't stand idly by in the face of injustice. Instead, the Angel feels compelled to act to save the galaxy and the universe that he loves. Before he fades forever, Merus says, "Goku... should you achieve Ultra Instinct at your current strength, it will be far more stable than before. You will not fall to Moro, nor to anyone else, for that matter." As the chapter comes to a close, Goku reels from the loss of Merus, and he's shown from behind while a lightning storm thunders in the background.

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Historically, the Dragon Ball franchise's biggest transformations have come after a major loss. In Dragon Ball Z, Goku transformed into a Super Saiyan for the first time after the death of Kuririn, and the visual language in Dragon Ball Super Chapter 63 suggests the same is about to happen here. This means Goku is likely to access true Ultra Instinct and wield it much more readily in battle, cementing him as one of the most unstoppable forces for justice in the universe. Merus' trade here is then that, while he himself cannot protect the universe without violating the law of impartiality, he can die, and thus spur Goku onto the next level. Merus, as an Angel, can't protect the universe in the name of justice, but Goku -- well, he did call himself the hope of the universe in Dragon Ball Z.

Dragon Ball Super Chapter 64 releases Sept. 18.

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