Trunks is a Saiyan-human hybrid, son of Vegeta and Bulma, from a dystopian future where Goku dies of heart disease before defeating the Androids. He travels back in time using a time machine to warn the Z Fighters, deliver heart medicine to Goku, and alter history to prevent the Android apocalypse. Upon arrival, he dramatically defeats Freeza and King Cold as a Super Saiyan, shocking everyone. Trained by Future Gohan, he achieves Super Saiyan power after Gohan's death. His efforts create a peaceful main timeline and eventually save his own future from Androids and later threats like Goku Black.