Trunks

There are two different Trunks in the Dragonball series. First is Mirai no Trunks (future Trunks), he grew up in a world torn by the evil Androids, the only other living Z senshi was Gohan, who became Trunks' teacher, who was later killed by the androids as well. As a final attempt to save the Earth, Bulma constructed a time machine to send Trunks back to before the Androids destroyed everything so he could warn Goku of the danger to come. Everything went as planned, except when Trunks went back to the past, he created an alternate universe, the Earth as it is in the series, and the Earth as it is after the androids got a hold of it. Mirai no Trunks first went Super Saiyan when Gohan was killed by the androids. Trunks later returns to the past to help the Z senshi in the fight against Cell.
Chibi Trunks (little Trunks) was born in the universe we know, and had no trouble going Super Saiyan. He was a little trouble-maker, and his partner in crime was Goten, who is only a year younger than Trunks. He is a bit spoiled but still a sweet kid. His father is Vegeta and his mother is Bulma, and he later has a younger sister named Bura.