TV-Series
Description
Merged Zamasu, also referred to as Fused Zamasu, is a major antagonist introduced in the Future Trunks Saga of Dragon Ball Super. He is the result of a Potara fusion between Future Zamasu and Goku Black. Goku Black is the original present Zamasu who used the Super Dragon Balls to switch bodies with Son Goku, while Future Zamasu is an alternate version from a different timeline who had already become an immortal being. The fusion combines the divine nature, immortality, and hatred of mortals from both individuals into a single, overwhelmingly powerful entity.

Merged Zamasu is characterized by an extreme and unshakable arrogance. He genuinely believes that he is the embodiment of divine justice and that his mission to eradicate all mortal life is righteous and necessary. This belief stems from his original experiences as an apprentice Supreme Kai, where he grew to despise mortals for their violence, ignorance, and misuse of power. In his fused state, this conviction is amplified beyond reason. He openly declares himself the supreme god and demands worship and praise from all who oppose him, often referring to his own form as beautiful, sublime, and invincible. Despite this godlike facade, his personality is fundamentally unstable. The fusion is composed of an immortal soul (Future Zamasu) and a mortal body (Goku Black), and this inherent contradiction causes his mental state to deteriorate rapidly when he is challenged or harmed. He can shift from calm, condescending declarations to furious, unhinged screaming, especially after sustaining damage. His hypocrisy is notable: he condemns mortals for their sins while willingly incorporating a mortal Saiyan body into his own being, justifying it as a necessary sacrifice to permanently cleanse the universe.

His primary motivation is the complete annihilation of all mortal life across every universe. He views this as the only way to create a perfect, peaceful world ruled exclusively by gods. This plan is known as the Zero Mortals Plan. He sees himself as the ultimate judge and executioner, and he believes that any god who is too weak to destroy evil is worthless.

In the story, Merged Zamasu serves as the final antagonist of the Future Trunks Saga. He is created during the climactic battle in the ruined future timeline, after the heroes gain the upper hand against Goku Black and Future Zamasu individually. The fusion proves to be far more powerful than Goku or Vegeta can handle alone, forcing them to also use Potara earrings to become Vegito. Even Vegito's tremendous power cannot permanently defeat the fusion due to his immortality. The battle causes Merged Zamasu's body to become increasingly corrupted, with half of his form mutating into a grotesque purple substance. After his physical body is destroyed by Future Trunks's Spirit Sword, his will and consciousness survive as a non-corporeal entity called Infinite Zamasu, which spreads across the entire universe. This threat becomes so dire that the only solution is for Goku to summon Zeno, the Omni-King, who erases the entire future timeline.

Key relationships include his connection to his component selves: Future Zamasu and Goku Black. He is essentially the two versions of Zamasu acting as one being. He holds bitter contempt for Goku, Vegeta, and Future Trunks, viewing them as the ultimate symbols of mortal rebellion against divine order. His relationship with his former master, Gowasu, is also strained, as he dismisses Gowasu's teachings about balance and compassion.

In terms of development, Merged Zamasu begins as a composed, godlike figure who believes he is invincible and infallible. As the battle progresses, his physical corruption mirrors his mental decline. He becomes more erratic, maniacal, and desperate, eventually losing all pretense of calm divinity and revealing the raw, destructive hatred inside him. This transformation is a direct result of the unstable fusion between his immortal and mortal components.

Notable abilities include superhuman strength, speed, and reflexes far beyond a Super Saiyan God Super Saiyan. He is permanently in the Super Saiyan Rosé form, which is the divine Saiyan transformation unique to Zamasu in Goku's body. His immortality makes him nearly impossible to kill, as his body can regenerate from severe damage. He can project blades of divine energy from his hands, use a powerful lightning-based attack known as Holy Wrath, and create a massive energy sphere for Divine Wrath Purification. He also uses a technique that summons a blinding light of divine justice, which initially heals his wounds but later accelerates his corruption. His Time Ring allows him to move between timelines, and as Infinite Zamasu, he becomes an intangible, expanding force that merges with the fabric of reality itself.