Majin Buu Saga

The final saga introduces the shape-shifting Majin Buu, Gotenks' fusion, and culminates with Goku's Spirit Bomb victory fueled by Earth's entire population.

The Buu Saga is Dragon Ball Z's final arc and its most deliberately surprising — a story that begins as a lighter tournament adventure and then reveals itself as an examination of everything the series has built, testing its heroes' relationships and values against a threat so fundamentally different from its predecessors that it requires new solutions entirely. The arc begins with the World Martial Arts Tournament and the introduction of Gotenks, the fusion of Goten and Trunks, suggesting a playful tone. Then Majin Buu is released — an ancient magical creature of pure, childlike destruction, who kills not from malice but from an absence of the concepts 'right' and 'wrong' — and the saga's color changes entirely. Buu's various absorptions and transformations, culminating in Super Buu and the nightmarish Kid Buu, force responses from the heroes that previous villains never demanded. The Fusion Dance, Vegeta's final sacrifice and eventual regeneration, the trip inside Buu to rescue absorbed friends — all reflect a series willing to try structural experiments its earlier arcs would not have attempted. The arc's true climax is Goku's final battle against Kid Buu, not as the unstoppable force of the Frieza fight but as a desperate hope that the pure-hearted people of Earth will give him the energy he needs through a Spirit Bomb. The Buu Saga resolves Dragon Ball Z's longest unfinished business: Vegeta's acknowledgment, finally and honestly, that Goku is the better man — the moment the two rivals' relationship finds something like peace.