Future Trunks is the half-Saiyan, half-Human son of Vegeta and Bulma from an alternate future and a supporting protagonist in Dragon Ball Z & Dragon Ball Super.
Well-mannered, serious and very cautious, Trunks hails from an alternate timeline in which Android 17 and Android 18 murdered the Z Fighters and proceeded to create apocalyptic hell on Earth. Trunks is trained by Future Gohan as a teenager and becomes a gifted fighter, swordsman and a Super Saiyan; traits that aid him greatly in the battle against the Androids after traveling back in time in order to save his own future. He makes his return in Dragon Ball Super to warn the Z Fighters about Goku Black & Zamasu.
For his present self, go to this page.
Personality
Future Trunks is very serious and cautious, due to the world he grew up in and having not grown up with his father, as well as polite and good-mannered. He usually thinks certain things matter and others don’t due to being from the future (though he is usually right). However, Trunks is surprised on a deep level when things happen differently from his timeline. He has demonstrated some cockiness, though only rarely, and in combat, he is usually serious and determined.
In Super, Trunks' PTSD resurfaced when the mysterious entity Goku Black appeared and causes so much destruction (to the point that he had a hard time being comfortable while in the present), he eventually feels better after seeing Gohan and his family. During his training with Vegeta in the past, Trunks only reason for wanting to become strong was to defeat the current threat that plagued his timeline, however after listening to his father's words, Trunks resolves to become strong and consistent in order to defeat and surpass Goku Black.
Synopsis
Early Life and Becoming a Super Saiyan
Trunks was born in Age 766 and in his timeline, Goku died from a heart virus shortly after he was born. Six months later, all of the other Z-Fighters except Gohan were killed in a battle with the powerful Androids, 17 and 18, and because of Piccolo's death, the Dragon Balls permanently disappear, which also kills Kami as all the Z-Fighters are unable to be wished back. The two proceeded to rampage across Earth for the next thirteen years and Trunks eventually became Gohan’s student so he could help fight the androids. He tried to help Trunks become a Super Saiyan, which was the only chance he had of fighting the androids. But he had yet to undergo the trauma usually needed to perform the transformation into Super Saiyan form. As 17 and 18 launched another attack, Trunks and Gohan went to fight them, but due to his lack of experience, Trunks ended up cornered by 18. Gohan took the hit to save him, losing his arm in the process, causing a severe lack of confidence in Trunks. He continued to try and reach the Super Saiyan form, but still kept failing to do so. After #17 and #18 began attacking again, Gohan knocked out Trunks so that he would not interfere, knowing that the androids would kill him if he tried to fight. But despite his abilities, Gohan was unable to fight them both and 17 and #8 eventually killed him. Trunks found his body, which finally pushed him enough to transform into a Super Saiyan. He spent the next three years training to avenge the friends and allies he’d lost to the androids, but could never beat them. After barely avoiding getting destroyed in one battle, Bulma showed Trunks a time machine she had been working on. She hoped he could use it to prevent Goku’s demise and prevent the future they lived in from coming about.
Delivering a Warning
Trunks uses the time machine to head 20 years into the past to warn Goku and the other Z Warriors of the coming android threat, as well as to give Goku the medicine that would cure his heart virus. Upon arriving, Trunks came across a cybernetically restored Frieza and his father, King Cold, who had come to Earth seeking revenge against Goku by destroying those he cared about along with Goku himself. Frieza didn’t think that the 17-year-old Trunks was much of a threat and at first was content with letting his soldiers handle it. However the half-Saiyan easily took down all of them, much to Frieza’s irritation and Trunks, taking his Super Saiyan form, gave him three chances to try and take him down. Every attempt was easily countered by the young Super Saiyan, causing Frieza to get more and more frustrated. Finally he attempted to use his Supernova Death Ball, which at first seemed to work, but Trunks actually just caught the attack. He taunted Frieza by jokingly saying he must have “dropped it” and the warlord blew up the ball with an energy blast in another attempt to kill Trunks. However, even this could do nothing to the young Super Saiyan, who fired a Burning Attack at Frieza from behind, making him jump into the air to dodge it. Trunks then slashed the cyborg in two with his sword, before slicing him into smaller pieces and blasting him into nothing. The young Super Saiyan was then approached by King Cold, who offered him a place at his side. But Trunks refused and the alien asked to see his sword, so the half-Saiyan gave it to him. However, King Cold actually believed the young Super Saiyan had only beaten Frieza because he had the sword and attacked him with it. Trunks easily caught the blade and fired an energy wave through King Cold’s chest. He begged the young Super Saiyan not to destroy him, offering him planets to rule. But Trunks was aware of how Frieza's family worked and finished King Cold off with a final energy blast. After destroying King Cold’s ship, the half-Saiyan approached the Z Warriors, telling them where Goku would land. They went to wait and though the Z Warriors asked him numerous questions, Trunks politely refused to answer. After Goku finally landed, the half-Saiyan asked to speak with him privately, telling him about the coming threat of the androids, as well as that he was Vegeta and Bulma’s son and also tells Goku that he will die of a heart virus before the androids' arrival. Trunks gave Goku the antidote to the heart virus he would get, then told him not to reveal any of this to the other Z Warriors since if Vegeta and Bulma found out about him, he might not be born. Trunks then headed back to the future, not realizing he had inadvertently caused things to happen differently.