Future Trunks
Trunks is a fictional character in the Animes Dragon Ball Z and Dragon Ball GT. He is a Halfbreed Saiyan.
There are two versions of Trunks during the series, and each will be detailed seperately.
Future Trunks
This is the first Trunks we ever see in Dragon Ball Z, and he is from a future alternate dimension, where the evil Android 17 and Android 18 are using the Earth as a playground, doing what they wish, due to being the strongest beings at the time. Future Trunks travels back in time to warn Goku about the Android threat in the future, in the hopes that they would be able to train to a power level high enough to destroy them.
In this alternate future, Vegeta died in the fight against the Androids, along with all of the Z Fighters apart from Gohan, who is his first mentor and martial arts teacher. As a result Trunks did not know his father at all, as he was only an infant at the time, and so when he finally meets his father in the past, he is seen to be constantly trying to impress him.
When they train in the Hyperbolic Time Chamber together Trunks surpasses Vegeta in power, due to being a Halfbreed Saiyan. Throughout the year that was spent in the Time Chamber, Trunks realised Vegeta's real sense of Saiyan pride. With this knowledge in mind, Trunks hid his true power level to spare what pride Vegeta had left. Trunks had managed to reach what is called a Ultimate Super Saiyan, where the Saiyan is still Super Saiyan 1, but have trained a lot and are on their way to Super Saiyan 2. In this form, if they power up enough, their muscles will expand a lot and because of this their speed decreases.
Trunks is the first Saiyan to take on Perfect Cell with the intention of destroying him, although Trunks' power was enough to deal signifigant damage to Cell, Trunks was too bulky and slow, and this gave Cell the upper hand. Trunks quickly realised that he was too slow and gave up hope right before Cell's eyes. The battle hungry Bio Android, however, was entrigued at how strong Trunks had become in such a short time and posed a challege to the fighters of Earth (Z fighters, Vegeta, Picollo, Gohan and Android 16) to power up and train as much as they could over a period of nine days. Then at the end of these nine days all the fighters of Earth must compete in the Cell Games. Trunks then left the battlefield and spread the word about the Cell Games, then when he reaches Kami Tower he declares a position in the "Hyperbolic Time Chamber" and trains for ---- a whole year in one day.
When Trunks emerges from his training he is powerful enough to compete in the games and although he wouldn't be able to take on Cell alone, he is definately strong enough to return to his time and Destroy Android 17 and Android 18. With nothing to lose Trunks left with all the fighters of Earth to where Cell awaits. Trunks never gets the opportunity to kill Perfect Cell and during the fight between Gohan and the Bio Android, Trunks is impaled through the chest with a powerful energy blast and left for dead.
Trunks remains dead until he is revived by Dende's Shen Long at Kami's Tower and well after Perfect Cell is dead.