In Future Trunks' timeline, Goku died of a mysterious heart disease after returning from the planet Namek... which not only caused a huge void for the Z Warriors but also This forced Gohan to grow and mature quickly so that in this way he would fill the void that his Father left.. What no one knew is that Androids: 17 and 18 would activate and begin to destroy the entire world!.. the Z warriors tried to stop them but most of them died.. (Including Vegeta, Piccolo, Krillin, Yamcha and Ten)