Future Trunks

Future Trunks (Trunks of the Future) is the Saiyan and human hybrid son of Vegeta and bulma from an alternate timeline. By the time present trunks was born, the timeline had been altered by Future Trunks' and Cell's trips to the past had occurred. Therefore, the two Trunks had completely different lives (as opposed to those who lived before the time machines arrived – they lived the exact same lives as their counterparts until the point at which the two timelines diverge, three years before the androids). "Mirai" is the Japanese Kanji name for 'future'. This is the first Trunks that the readers and/or viewers ever see in the manga and anime. Trained by the alternate timeline's Gohan, Future Trunks travels through time to seek help from Goku to prevent the from ravaging the world, like they did in his dark future. Future Trunks is a loyal and uncompromising warrior, and can be slightly cocky at times. He inherited his mentor's do-or-die attitude, as well as his father's brash confidence (though he displayed less of it at different times; it was most on display in his fight against Mechen friza and King cold). He wields a sword of unknown origin.

Personality
Future Trunks, having never met his father or grew up under his influence, combined with the fact that he grew up in an apocalyptic world, is very cautious and serious (such as when he did not want Vegeta to trust Paragusin Dragon Ball Z: Broly - The Legendary Super Saiyan), unlike his main timeline counterpart, who had a personality very similar to his father's. Future Trunks feared the Androids, panicking at the introduction of Android 16, and before going back in time, was very respectful to everyone, especially his mother and master.

Because he comes from the future and believes he knows what is going to happen, Future Trunks is usually shown thinking that only some things will matter and others probably won't (although he is usually right in the long term). This is shown in, at first, his resistance to do anything unless Goku is present. Other things, such as his surprise that Piccolo's fusion would make a difference, also show this. As such, he is usually surprised at events (on a different layer than the fact that history was different from his recollection). He is even (though very rarely) shown to be cocky, such as when he became an Ultra Super Saiyan - but when he loses his seeming "advantage" this cockiness dissolves instantly. Molded from his dark timeline, he is very serious and is a determined fighter like his father. He is also the only full or half-Saiyan that doesn't display a voracious appetite at some point during the series, with the exception of the History of Trunks special, when he imitates his mentor Gohan's eating habit.

Unlike his father or alternate timeline self, Future Trunks is often shown to be very polite and well-mannered. This is clearly shown in the original version through his speech, as he is often heard using the polite form of Japanese phrases when addressing his allies. After returning to his timeline to defeat the androids, he is never seen in the series again. In Dragon Ball Z Movie 9 while talking to Chi-Chi, Bulma states that Future Trunks came back to the past one last time to enter the World Tournament. In an interview with Akira Toriyama when asked by a Trunks fan what had happened to Future Trunks and the Majin Buu of his timeline, he stated that he didn't realize that the series was going to continue past the Cell Saga, and that it was supposed to be the final chapter in the Dragon Ball series. However, due to overwhelming demand from Japanese fans, he continued the series.

Time travel
In Age 784, Trunks travels back in time 20 years, in order to warn Goku about the android threat in the near future, as well as to deliver medication that will cure Goku of the heart virus that he is supposed to die from. However, upon arrival he is greeted by Frieza with his father King Cold. They had come to Earth in order to seek revenge upon Goku's loved ones, and to kill Goku himself. Trunks, then seventeen years old, did not look like much of a threat to Frieza, and he freely told him so. Trunks implies his ability to transform into a Super Saiyan, but Frieza, albeit initially shocked, laughs it off along with his father. Trunks, anticipating that Frieza doesn't believe him, proves it by transforming, to Frieza's horror. Frieza was then given three opportunities to kill Trunks, but the young Super Saiyan was able to block and dodge the attacks with ease (and kill all the minions he had brought to Earth with his father) to great frustration of Frieza. Frieza then turns angry and fires a Supernova (the same attack he used to blow up Planet Vegeta) at Trunks. Future Trunks slices Mecha Frieza in half with his sword Trunks just catches the attack and tells Frieza that he must have "dropped it," after which Frieza detonates the blast with an energy wave (only in the anime, while in the manga Frieza never tried a planet-busting ki attack, and fired this blast immediately instead). Trunks then easily remains unscathed and performs what he calls the Burning Attack to have Frieza dodge the blast, which is followed up by his sword (Shining Sword Attack). Trunks getting attacked by King Cold Frieza, cut in half, was completely destroyed by being hacked to bloody chunks and then blown to dust in an instant, and was soon followed by his arrogant father King Cold, who was killed by an energy beam. Trunks offers the Z Fighters a drink from his cooler in a capsule, and waits for Goku to arrive. Trunks later finds out, to his chagrin, that he interfered with the timeline unnecessarily. Goku, although miles away in space, was prepared to step in using his Instant Transmission technique (just as he did in Trunks' original timeline) when Future Trunks showed up, and killed Frieza himself.

When Goku arrives, Trunks informs Goku of the future where the Androids arrive and kill all of the Z Fighters in a large battle, also telling Goku not to inform anyone about it, however Piccolo's sensitive Namekian ears pick up the conversation and tells the Z Fighters of the future, inspiring the heroes to train their hardest for the next three years. However, inadvertently, Trunks' revelation of the future alters it slightly.