Man you guys need to see Dragon Ball GT Trunks Pan and Goku San "kid" become a bigger role even though goku was already a big role. If you haven't heard the story line, what happends is there are black dragon balls... some call them "evil dragon balls" "super dragon balls" or just plain "black dragon balls" Well they are found in the middle of kami's place, and they are super powerful of course but it has this stupid effect, where after you wish instead the dragon balls going around the world, instead they go around the universe, and worst of all they destroy the planet they were wished on after a certain amount of time, like a year. Well, anyways some one wished Goku to a "kid" form... it didnt make goku weaker it just made it so he had time to grow up and become stronger. Anways, Pan Goku and Trunks go around searching for the balls. Meanwhile the planet earth has to be looked over by Uub, vegeta, gohan and the rest of the z fighters. In the end of the series the dragon ball gt the dragon balls were wished too many times by evil people so the balls split into 7 evil people, the Evil Shenrons,(also goku formed with the other dragon, so he could do the most powerful move called "The Dragon Punch" in which the eternal dragon a yellowish form of the eternal dragon comes out of his hand and screws guys up) anyways goku ssj 4 and vegeta ssj 4 have to fuse together using the fusion and they become Gogeta SSJ 8, Although Vegeta needs the help of Bulma to make vegeta ssj 4 because vegeta is not as strong as goku.
P.S. I like trunks, not that hes the fastest melee but he has fast beam attacks making it so he can strike while they are down, also like piccolo's special beam cannon!