Zamasu

Goku Black (ゴクウブラック), is a fictional character and antagonist in the Dragon Ball Super series created by Toei Animation. He is introduced in the forty-seventh episode of Dragon Ball Super anime which first aired on June 12, 2016 and in chapter #14 An SOS from the Future!! (未来からのSOS!!) from the manga. He is one of the main antagonists in the Future Trunks Saga.

Goku Black is an entity that resembles Son Goku, and referred to himself as such before being given the name "Goku Black" by Bulma. He wears a single Potara earring and a Time Ring, the latter of which allows him to travel between different timelines at will. He wreaks havoc in Future Trunks' timeline, bringing humanity to the brink of extinction. As he explains to Future Trunks, he has come to believe that only the decimation of humanity, which he views as corrupt and violent, can make Earth a utopia setting with Future Zamasu.

It is later revealed that Goku Black is Zamasu (ザマス) (spelled Zamas in the manga), an apprentice from Universe 10. In the anime's original, unaltered timeline, Zamasu hijacked Goku's body using the Super Dragon Balls as part of his plan to attain supreme power and wipe out all mortals. Although Beerus manages to go back in time and kills Zamasu, Goku Black's Time Ring prevents him from being erased from existence. To complete his plan, he joins forces with the Zamasu of Future Trunks' timeline, who uses the Super Dragon Balls to become immortal.

Creation and conception
Notes by creator Akira Toriyama state Goku Black has access to both the Super Saiyan and Super Saiyan Rosé forms.

Zamasu is a green-skinned humanoid with grey eyes and a white Mohawk. He is seen wearing a violet long-sleeved shirt under a gray coat with yellow trimming, itself under a light blue sash. He also wears dark blue pants and white boots. The Zamasu who stole Goku's body originally had an appearance identical to his counterparts. He gains Goku's appearance after switching bodies with him, the only physical differences being a slightly darker skin tone and sterner eyes, along with a somewhat skinnier physique after the switch. His attire consists of a sleeveless dark grey uwagi, a long-sleeved black undershirt with a turtleneck, a red sash, black pants and white boots. He wears a single gold and green Universe 10 Supreme Kai Potara earring on his left ear. He also wears a Time Ring on his right index finger, that he uses to travel through time without the need of a time machine. After attaining his Super Saiyan Rosé transformation, his hair rises upward and turns bright pink.

After Goku Black fuses with Future Zamasu, the end result is the even more powerful Merged Zamasu. This character has a close resemblance to the original Zamasu, but his hair is styled like Goku Black's Saiyan transformation and his clothing is black and red. After taking enough damage, Goku Black's mortal body conflicts with Future Zamasu's immortal body. This causes half of Fusion Zamasu's body to become purple and distorted, weakening his healing factor. Toei Animation Producer Atsushi Kido said Fusion Zamasu was a "cheat" character for his massive strength, and that his one weakness could be that he was originally a single person.

Dragon Ball Super
Goku Black first appears in Trunks' timeline and after killing Bulma, chases down Trunks until he flees to the past. A short time later, Goku Black makes his way to the past through a time portal. He has a short battle with Goku when the time portal begins to collapse. Before Goku Black is pulled back into the portal, he destroys the time machine to prevent others from returning to the future. Goku Black strives to increase his strength through a rematch with Goku upon discovering the encounter increased his power. Goku, Whis and Beerus travel to Universe 10 after tracing Goku Black's energy there, encountering apprentice Kaiō-shin Zamasu, who Goku bests in combat, and his master Gowasu. As a result of his loss to Goku, Zamasu then begins to descent into madness as his intolerance for mortals grows stronger. After Goku, Vegeta and Trunks travel to the future using another time machine, Goku Black confronts them, attains his Super Saiyan Rosé form, stabbing and thereby critically injuring Vegeta, and fighting an evenly matched battle with Goku, before that timeline's version of Zamasu interrupts the fight. Goku Black and Zamasu are revealed to be working together; their combined effort overwhelms Goku and Trunks, though the two and Vegeta escape to the past. The present version of Zamasu comes under suspicion, Whis discovering his intent to kill Gowasu, reversing time to undo the event and Beerus killing Zamasu after he attacks Goku. The trio of Saiyans return to the future and during the encounter, Goku Black reveals himself to be Zamasu from another timeline who after stealing the body of Goku, proceeded to kill him, Goten and Chi-Chi. Goku Black and Zamasu overcome Goku, triggering Trunks' transformation into a new Super Saiyan form, Super Saiyan Rage. Goku Black and Zamasu combat Trunks while Goku and Vegeta return to the past, Goku learning the Demon Sealing Wave while Vegeta trains in the Room of Spirit and Time. The two are able to overcome Trunks, though he is saved from death by the resistance and a returning Vegeta who overpowers Goku Black. Future Zamasu is nearly sealed away by Trunks and Mai, the event along with Goku Black's losing to Vegeta, causes the pair to realize they have underestimated their enemies and fuse into Fusion Zamasu. Fusion Zamasu easily overwhelms everyone, forcing Goku and Vegeta's fusion into Vegito, who is able to match him in strength and even overpower him, before the fusion abruptly ends. Trunks then gains power from every remaining living thing on Earth, channeling it all into his sword and allowing him to slice Fusion Zamasu in half. Fusion Zamasu reemerges, as an energy entity that corrupts the entire alternate future universe after his physical body is destroyed, known as "Infinite Zamasu", and kills everyone on Earth apart from Goku, Trunks, Vegeta, the present version of Bulma, Mai, Gowasu, and East Supreme Kai. Out of options, Goku then summons the alternate future counterpart of Zenō-sama, who erases Zamasu from existence, along with the entire multiverse of the alternate future timeline out of disgust for his actions, killing him at last and saving the present.

In Toriyama's films and in other media
Goku Black appears in Dragon Ball Z: Resurrection 'F' Future Trunks Special Edition attempting to kill Trunks but being prevented by Mai's intervention, this appearance taking place before his initial appearance in Dragon Ball Super.

Goku Black is a playable character in Dragon Ball Xenoverse 2 as a pre-order bonus / downloadable character while Zamasu and Goku Black (Super Saiyan Rosé) are playable characters in the Pack 3 DLC, and Fused Zamasu is playable in the Pack 4 DLC. They also appear in Dragon Ball Fusions.

Abilities
Goku Black and Zamasu possess several abilities including superhuman strength, speed, reflexes, and energy blasts, which can be utilized by the use of ki. Their main technique is Aura Slide (神裂斬), which allows the user to project an energy blade from their hand.

As he possesses Goku's body, Black is able to perform most of Goku's abilities, especially his signature move, the Black Kamehameha (ブラックかめはめ波) and his teleportation skill, taught by the inhabitants of the planet Yardrat. Grown unbelievably strong from his fight with Goku, Black learned more of Goku's fighting style and has become a, his version of Super Saiyan (Super Saiyan Blue in the manga and Akira Toriyama's notes) which the hair is pink because of his status as a god. This form allows Black to perform a variety of unusual techniques, among them the creation of scythes and Ki swords that are thrown to the opponent to create a crack towards other realities, which in turn can be used to create clones of himself. The manga has him transforming into a instead of his Super Saiyan Rosé state (which he transforms into later on) against Super Saiyan 2 Vegeta. It is stated by Trunks that Black was already able to become a Super Saiyan but had gotten the power where he simply did not need the form.

Merged Zamasu has several unique abilities, including the Blades of Judgement (裁きの刃), energy blade barrages that will explode upon contact with the ground, the Barrier of Light (光の壁), which prevents Zamasu from being struck by attacks while striking back combatants with blasts of lightning, and the Holy Wrath (聖なる逆鱗), an energy sphere that enlarges after being thrown. Goku Black's half allows Merged Zamasu to become stronger when put in near death states, but this half also causes drawbacks for his immortality, which is reduced to high durability, and a healing factor that is uneven for half of his body, giving the inferior half a grotesque appearance. Merged Zamasu's strength is shown to be massive, nearly killing Super Saiyan Blue Vegeta in a single blast, and is on par in strength with Super Saiyan Blue Vegito. In his bodiless state, Merged Zamasu retains much of his power, able to overwhelm Goku, Vegeta and Trunks and his attacks are powerful enough level the Earth's surface to nothing, killing the last of the few survivors of Goku Black's year long reign of genocide with Chou Makouhou Barrage (連続超魔口砲口エネルギー波バラージュ), and to rip across multiple timelines, as he is detected by Beerus and Whis in the present timeline.

Voice actors
Zamasu is voiced by Shinichiro Miki in Japanese media.

In all media, Goku Black shares his voice actor with Goku. He is voiced by Masako Nozawa in Japanese, and Sean Schemmel in the English dub.