Goku Black

Goku Black (mainly just referred to as Black) is one of the two main antagonists (alongside Future Zamasu) of the Future Trunks Saga of Dragon Ball Super. He is a mysterious and evil being who bares a striking resemblance to Goku and has caused the Earth's second apocalypse in Future Trunks' timeline.

Eventually though, it is revealed that he is the original incarnation of Zamasu, having switched bodies with Goku before killing him. He is one of the biggest threats in the entire Dragon Ball franchise as he poses a threat to all time and space. Black is the most evil version of Zamasu. He is the mastermind behind the Zero Mortal Plan and specifically recruited his future self to assist him.

He was voiced by Masako Nozawa in the Japanese version, Sean Schemmel in the English version.

Appearance
"He wears black clothing, so we call him "Goku Black""

- Future Trunks telling Goku about Goku Black. Black's original appearance was the same as his other timeline counterparts. After stealing Goku's body he underwent some physical changes. While still looking identical to Goku, he has a more thinner physique and facial structure. His eyes are more sharper and has a somewhat younger look then Goku. His Gi consists of a sleeveless dark gray jacket, a long-sleeved black undershirt, a red sash, black pants and white boots. He wears a single earring on his left ear and a silver Time Ring on his right index finger. When concealed in dark clouds or fire, Goku Black has the appearance of a demon from hell.

Personality
Goku Black is extremely intelligent, methodical, ruthless, diabolical, and manipulative. He has killed many humans including Future Bulma without a second thought saying it was in the name of "Justice". During his fight with Future Trunks, he was enjoying the battle and demonstrates a sense of brutality as he savagely kicks Trunks' right arm breaking his bones and then shoots a barrage of Ki blasts at him.

Also judging from his derogatory and opprobrious comments about Trunks's Saiyan heritage, it is possible that he has some negative feelings towards those with Saiyan blood. Yet at the same time refers to them as a proud warrior race, and finds Trunks's unbecoming tactics for a Saiyan disgusting.

He is also highly respectful for Goku, saying that is a honor to fight him. He also shares a few traits with Goku, namely his desire to fight strong opponents and love for combat, even going as far as not using his full power at the beginning of the battle to have a good fight. While he does respect him, he is no less willing to kill him than any other mortal. Black shares Goku's determination, after seeing Future Trunks disappear in the Time Machine, he promises to find him while claiming that there is nowhere for him to run.

Goku Black utterly detests humanity, perceiving them as a sacrilegious blasphemy and God's greatest mistake. He elaborates this by stating that he has scoured several universes and has implied to have seen enough timelines via Time Ring to feel vindicated in his belief that humanity is an existence that prevents the universe as a whole from becoming a true paradise and has taken upon himself to destroy all traces of mankind, whom he believes have only been allowed to live as long as they have because the Gods to acknowledge their failure in creating humans.

He also shows masochistic traits, such as taking a full-force punch from Future Trunks while laughing, and seemingly enjoys the pain inflicted to him by Goku. However, he is slightly irritated, hot-tempered, and argumentative, when Trunks threw his sword at him, in order to intercept Black's charged ki blast.