Zamasu, who came to be known as Goku Black or Evil Goku after stealing the body of Goku, is a Supreme Kai and the former North Kai of Universe 10. He along with Future Zamasu are the main antagonists of the Future Trunks Saga of Dragon Ball Super. He was given the name "Goku Black" by Future Bulma when he initially referred to himself as Son Goku.
However, the present Zamasu was still alive, despite the flow of time having changed as the result of Future Trunks going back to the past. Zamasu in the original flow of time succeeded in carrying out his plans to kill Gowasu and take his Potara Earrings and Time Ring. Following this, he used these items to gather and use the Super Dragon Balls to switch his body with Goku, becoming Goku Black, and traveled to Future Trunks' timeline and allying with his counterpart there. As Goku Black, the Time Ring he wore stopped him from being erased from existence once his past self was "killed", after time had been altered.
In the midst of causing destruction, Black began to sense Trunks's ki, so he then pursued him. After Black caught sight of Trunks, he fired several ki blasts at Trunks while he was attempting to flee but failed and he was hit by a ki blast. While Trunks was on the ground defeated, Black declared it was over for Trunks as he prepared a ki blast to kill him. However, Future Mai saved Future Trunks by throwing a flash grenade at Black and then they both quickly escaped. After Black regained his sight, Black stated that Trunks could not run forever.
Using a wish from Super Shenron, Zamasu switched bodies with Goku. In this form he became known as "Goku Black".
Super Saiyan Rosé
Black possessed the ability to become his own version of a Super Saiyan, which matches Super Saiyan Blue in strength. Black stated that he fully mastered Goku's power to be able to achieve Super Saiyan Rosé.
A powerful fusion born between the union of Future Zamasu and Black by the Potara earrings.
A game-only fusion born between the union of Broly and Black through EX-Fusion in the game Dragon Ball Fusions.