Future Zamasu bears an identical appearance to his past counterpart. He is fairly tall and lean in build with pale green skin, gray irises, and a white mohawk. He wears a slim violet long-sleeve shirt, baggy blue pants, white boots, a black Supreme Kai vest with yellow trimming, and a pale blue sash folded over his abdomen. Unlike his counterpart however, he wears a single green and gold Potara earring on his left ear.
Zamasu, compared to his other counterpart, has truly fallen into the depths of evil, speaking of all Earthlings and Saiyans "mere humans" who are inferior to him. Similar to his partner Black, he has a sadistic goal of ridding the entire universe of humans, believing them to be the source of all evil, and he refers to a world without humans as a "utopia". Zamasu also seems to have a deep hatred for Goku, as he considers killing him as his main goal and something only he should do (a trait his past counterpart shares). It is speculated that due to Zamasu's obsession with Goku, he used the Super Dragon Balls to wish for a servant befitting of him with Goku's exact appearance, creating Goku Black. While battling Goku and Trunks, he constantly speaks about how humans misuse their "god-given wisdom" for their own personal gain. Also, Zamasu refers to his immortal body as befitting for him.
Similar to his counterpart, future Zamasu was once a Supreme Kai apprentice training under the Supreme Kai, Gowasu. He also at some point met Goku as evidenced with his hatred for the main timeline Goku shown in the series. After this, Zamasu sunk into darkness, his hatred for humans becoming stronger than ever. He soon created a plan to annihilate mortals to shape the world in his own image. Unlike his counterpart however, future Zamasu succeeded in killing his master, inheriting the Time Ring and the rank of Supreme Kai. He then traveled to Universes 6 and 7 to gather the Super Dragon Balls, wishing for immortality. With no one standing in his way, Zamasu then initiated his plan: to kill "unnecessary" humans in order to bring "justice" and to create a "utopia". However, in order to complete his plan, he would have to look for a universe without a God of Destruction, as Supreme Kais are not allowed to lay a finger on the planets. With that being said, Zamasu searched for universes in many different realities without a God of Destruction. During the search, he met an entity who had a body similar to Goku, with the same goals in ridding the world of humans. They soon allied themselves and continued their quest. Black finally found a universe in an alternate timeline. A timeline in which the God of Destruction in their Universe was deceased. Black then executed the plan, killing as much humans as possible while Zamasu stood back, watching his plan unfold.
Dragon Ball Super
"Future" Trunks Saga
Zamasu appeared standing side-by-side with Black during his battle with Goku. Zamasu descends from above in a bright light, reminding Black of his promise to allow him to kill Goku and attacks Goku at the same time with Black, forcing Trunks to jump in and even up the fight. During the fight, Trunks is fighting evenly with him as a Super Saiyan 2, but when Trunks stabs him in the stomach with his sword, he instantly heals his wound. Zamasu also emerges unscratched from Future Trunks' Final Flash, revealing his body is immortal. Goku regroups with Future Trunks as Goku Black charges a Kamehameha, with Zamasu grabbing them and holding them in place to prevent them from escaping. Goku and Trunks are defeated by the attack, and Zamasu remained unharmed due to his immortality. With Black, Zamasu prepares to finish off the two Saiyans, but they are interrupted by Vegeta, who woke up and intercepted their attack but fell back unconscious immediately after.
In the confusion of the attack, Goku and Trunks have disappeared, so Future Zamasu and Black prepared to finish off Vegeta, but they are forced to fall back when members of the Resistance fire tear gas at them. The two then spot the time machine with the beaten Trunks, Vegeta, and Goku inside, and try to intercept it, but are too late. Zamasu exclaims they will return eventually, and when they do they will meet their end.
Both Future Zamasu and Black are next seen at the cabin they are living in. Black is ready to kill Goku once and for all but Zamasu says that he shouldn't kill Goku right away or else Black won't get any stronger than he already is. He then offers Black the chance to become immortal, but Black refuses, saying he is satisfied with the power he has now.
Like his past counterpart, Zamasu is a fighting prodigy, and in between the time gap of the present and the future, Zamasu's fighting abilities increased significantly. Zamasu now possesses enough power to face Super Saiyan Blue Goku evenly in battle, and Super Saiyan 2 Trunks soon after. He can even hold down both opponents simultaneously long enough for Goku Black to strike them down.
Techniques and special abilities
- Flight - Zamasu is capable of flight using his ki.
- Energy Ball - Zamasu focuses ki to form a blue and black colored sphere, similar to Goku Black's.
- God Split Cut (神裂斬) - Zamasu concentrates ki around his hand and then uses it like a sword to slice opponents. He can also fire ki blasts from his Energy Blade from a distance.
- Continuous Energy Bullet - Zamasu is capable of rapid firing energy blasts from the hand that he is currently using for his energy blade.
- Immortality – The ability to remain unchanged by the passage of time, unable to die, and simply live forever. Obtained using the Super Dragon Balls. Due to his apparent immortality, Future Zamasu is only moderately unfazed by any injury, no matter how grievous. He is also apparently unaffected by energy attacks, as he took the full brunt of Future Trunks' Final Flash and Goku Black's Black Kamehameha without a scratch.
- Regeneration – Thanks to his immortality, Future Zamasu heals any wound he may incur within seconds.
- Ki Sense - Future Zamasu is able to sense the ki of other lifeforms.
- Japanese: Shin-ichiro Miki
- Future Zamasu and Goku Black (Super Saiyan Rosé) vs. Goku (Super Saiyan Blue), Vegeta (Super Saiyan Blue) and Future Trunks (Super Saiyan 2)
- Zamasu is the first character within the manga continuity to achieve immortality.