Barrier of Light

Immediately after the Potara Fusion between Goku Black and Future Zamasu completed, the newly formed Fused Zamasu activated the Barrier of Light. The halo appeared behind his back, combining the divine ki of Future Zamasu's immortal Kai body with the Saiyan power of Goku Black's stolen body. This combination produced a state that was both a defensive barrier and an offensive weapon: incoming attacks were repelled by the light itself, while Fused Zamasu could simultaneously fire Absolute Lightning, a barrage of purple energy bolts, from within the halo's radius.

Power and Collapse

The Barrier of Light raised Fused Zamasu's combat power to a level where he could challenge both Goku and Vegeta at once. However, the form proved to be unsustainable for an unexpected reason. Because Fused Zamasu contained the mortal Goku Black within him, the fusion's body was not truly immortal. Damage began to accumulate on the right side of his face, producing a grotesque purple discoloration that spread with each injury. As the mutation worsened, the Barrier of Light weakened and eventually dissipated entirely. Goku, using Super Saiyan Blue Kaio-ken, was able to break through the barrier with a God Kamehameha once Zamasu's body had degraded sufficiently.