La sfida finale

Goku's God Kamehameha tears away half of Fused Zamasu's face, revealing that his fusion is imperfect. Because Goku Black's body is mortal while Future Zamasu's is immortal, the merged form lacks stability. The right side of Fused Zamasu's body begins mutating into a grotesque purple mass. Despite losing the use of both arms from the strain, Goku uses Kaio-ken to land a final kick before collapsing. Gowasu identifies the weakness: the conflict between mortal and immortal halves creates openings, but exploiting them requires enormous power.

Goku proposes Potara fusion. Vegeta resists the idea but recognizes they have no alternatives. Gowasu explains that non-Supreme Kai fusions last only one hour. After eating their last Senzu Beans, Goku and Vegeta don the earrings, and Vegito emerges for the first time since the battle against Super Buu. He immediately transforms into Super Saiyan Blue, dubbing himself "Vegito Blue." The fused warrior dominates Fused Zamasu, stabbing him with a Spirit Sword and pointing out that fusing with a mortal body means Zamasu is no longer truly immortal.

But the fusion burns through energy at a catastrophic rate. Vegito fires a devastating God Final Kamehameha, and just as he teleports in for a finishing blow, he defuses, far short of the one-hour limit. Goku and Vegeta crash to the ground helpless. As Fused Zamasu prepares to end them, Future Trunks arrives wielding a sword of pure ki energy. Powered by the collective energy of every surviving person on Earth, channeled through a Spirit Bomb-like sphere of light, Future Trunks's blade grows into a massive cleaver of energy. He drives it through Fused Zamasu and slices him completely in half, ending the battle in one climactic stroke.

Fused Zamasu's mutation is the saga's cruelest irony. The being who sought perfection through godhood is undone by the very mortal body he stole. His deterioration reflects the fundamental contradiction in his philosophy: he despises mortals yet relies on a mortal's body for his power. Vegito's return is fan service done right, providing a spectacular but ultimately incomplete solution that passes the baton to Future Trunks. The early defusion makes narrative sense since the power required to fight as Vegito Blue exceeded the fusion's energy budget, preventing the climax from being resolved by a borrowed power-up.

Future Trunks's victory with the Sword of Hope draws on the Spirit Bomb's legacy while making it deeply personal. The energy comes not from a planet full of strangers but from the specific survivors he has been protecting throughout the saga: the soldiers, the children Haru and Maki, Future Yajirobe, Future Mai, and even Bulma. Goku and Vegeta contribute their remaining energy willingly, completing a transfer of responsibility to the saga's true protagonist. Future Trunks does not win because he is the strongest. He wins because he carries the hope of everyone who refused to give up.