Trunks

Trunks is the Saiyan/human hybrid son of Vegeta and Bulma and a hero from Dragon Ball Z (Kai) and GT.

Early Life
Trunks was born shortly before the appearance of the Androids and Cell to Vegeta and Bulma. He was with his mother throughout the conflict and was even around his older self from an alternate timeline, Future Trunks

World Martial Arts Tournament
Seven years after Cell was defeated, Trunks demonstrated great strength and power for his age, even more than Vegeta, Goku, and Gohan at that age. He spent a lot of time being trained by his father, but at one point, attained the ability to become a Super Saiyan. However Trunks did this without Vegeta’s knowledge and one day tried to train in the Gravity Room with his father, though it was a bit intense for him. The Saiyan prince suggested to Trunks that he leave, but he just transformed into a Super Saiyan and leapt around easily, much to Vegeta’s shock. The half-Saiyan competed in the 25th World Martial Arts Tournament along with many of the other Z-Fighters. Trunks easily fought his way through the Junior Division, reaching the Grand Finals where he faced off against his best friend, Goten, who was Chi-Chi and Goku’s second son. Trunks managed to win, though he broke a rule the Z-Fighters made earlier by transforming into a Super Saiyan (though to be fair, Goten did it first). For winning the Junior Division, Trunks got the chance to face Mr. Satan, who, knowing how much power he had, asked him to just lightly punch him in the face. However for the half-Saiyan, even a light punch sent Mr. Satan flying out of the arena, letting Trunks win. But the audience just thought he’d lost on purpose to be nice to the boy. Afterwards Trunks and Goten competed in the adult division by diguising themselves as the fighter, Mighty Mask. They fought in a free for all match with the other contestants, including Android 18, and engaged in a lengthy battle with the android. Eventually 18 used the Destructo Disc technique to cut Trunks and Goten’s costume in half, revealing their deception and disqualifying them.

Battle with Majin Buu
After finding out about the release of the monster Majin Buu from Videl, Trunks and Goten went to help fight him. As Vegeta struggled against the majin, Trunks jumped into help and tried to make his father let him and Goten help. However the Saiyan prince, having decided to sacrifice himself in an attempt to finish off Majin Buu, told Trunks he was proud of him and hugged him. Vegeta then knocked his son and Goten out and had Piccolo carry them away from the fight, bringing them to Kami’s Lookout to take shelter from Majin Buu. Upon waking up, Trunks and Goten found out that Vegeta and Gohan were both dead. Goku then told the two boys about the Fusion Dance technique would let them fuse into one more powerful fighter that could match Majin Buu. However Babidi sent out a message to the people of Earth, telling them he was after Trunks, Goten, and Piccolo. He found out Trunks was from West City and planned to head there with Majin Buu to destroy the city. Since they needed the Dragon Radar to find the Dragon Balls to bring back everyone killed in the conflict, Trunks flew to West City to get it while Goku kept Buu occupied. Thanks to his Super Saiyan 3 transformation, which impressed Trunks greatly, he was able to buy the half-Saiyan the time he needed to find the Dragon Radar. However the fight had cost Goku energy, reducing the time he had on Earth, and he began teaching Trunks and Goten the Fusion Dance. But at their request, he showed them how to become a Super Saiyan 3 first, costing him even more time. Eventually Goku ran out of time and left the job of teaching Trunks and Goten the Fusion Dance to Piccolo. After two failed attempts to fuse, Trunks and Goten successfully performed the Fusion Dance, becoming Gotenks. However Gotenks was far too arrogant and went to fight Majin Buu, but was beaten by the majin. After returning to the Lookout and defusing, Trunks and Goten fused as Super Saiyans and Super Saiyan Gotenks raced off to fight Majin Buu again. However since he spent too much time flying around the world, he defused back into Trunks and Goten before he could even face the majin. They flew back to the Lookout, where they took a nap, but as they were sleeping, Super Buu came into being and found the Lookout, now able to sense energy. After getting the majin to wait an hour, Piccolo had Krillin wake Trunks and Goten and take them to the Hyperbolic Time Chamber, so they could get in some more training. But as they were walking there, Super Buu killed Chi-Chi, when she confronted him about (apparently) killing Gohan, much to Goten’s horror. Trunks managed to give him a pep talk to pump him up to fight Buu and they went into the Time Chamber to train. However Super Buu lost patience after a half hour and demanded to fight immediately so Piccolo took him on the longest route possible to the Time Chamber. But Buu eventually got wise to what he was doing and Piccolo telepathically contacted Trunks and Goten, telling them he and Buu would arrive in 1 minute, which would be six hours in the Time Chamber. Thus they should take time to rest in preparation for the fight with Buu and Trunks and Goten prepared to fuse. They taunted the majin at first, but before they could fuse, he punched Trunks in the face. The half-Saiyan scolded him for doing so and told him to wait, before fusing into Gotenks and taking on Super Buu. However he couldn’t beat the majin, even after blowing him to pieces with the Super Kamikaze Ghost Attack and vaporizing his pieces. After Gotenks pretended to be out of energy to make the fight more spectacular, Piccolo blew up the entrance of the Time Chamber, trapping Gotenks, Super Buu, and himself inside. However the majin, enraged and horrified at the prospect of being trapped without candy forever, let loose a powerful scream that tore open a dimensional hole. Super Buu escaped through it and though Gotenks and Piccolo tried, they couldn’t do the same. However the fusion revealed he could transform into a Super Saiyan 3 and managed to do what Super Buu did, allowing Gotenks and Piccolo to escape. After getting out, Gotenks managed to put up a better fight against the majin, but as he prepared to finish Buu off, he started losing power and ultimately defused. Trunks, Goten, and Piccolo seemed to be doomed at Super Buu’s hands until Gohan, now greatly empowered thanks to the Elder Kai, arrived and fought him. He proved easily able to take on the majin, angering him to the point that he used a self-destruction attack, but when he regenerated, he hid for an hour. Upon showing himself, Super Buu demanded to fight Trunks and Goten fused as Gotenks again and the two boys fused into Super Saiyan 3 Gotenks once more. However this was all a trick and absorbed Gotenks and Piccolo into himself, becoming far more powerful. After Goku and Vegeta were purposely absorbed as Vegito, they rescued Trunks, Goten, Piccolo, Gohan, and the good Majin Buu from Super Buu. However this made him change into his original form, Kid Buu, and Trunks, Goten, Piccolo, and Gohan were killed when he blew up the Earth with his Planet Burst. But Trunks and everyone else on Earth were brought back by the Namekian Dragon Balls to lend energy to Goku’s Spirit Bomb, which he used to destroy Kid Buu.

10 Years Later
After ten years had passed, Trunks was forced by his father to compete in the World Martial Arts Tournament. When Goku realized that one of the competitors, Uub, was Kid Buu’s good reincarnation, he left to train the boy, wishing Trunks and the others good-bye.