Future Trunks literly came from the furture.Being killed by Cell in the future he came to our timeline .He arrived in well the Trunks saga of dbz and easily killed King Cold and Frieza.He knew Goku from the stories his mother told him but Goku did not know him.He was very strong for his age stronger than Vegeta he told Vegeta not to under estimate Cell's true power in his last form.Vegeta was not killed by Cell because Krillin took him away from the fight.Trunks was the first sayian to appear on dbz as a super sayian already.
