Manga
The creator of Dragon Ball wanted to permanently kill and replace Goku
Akira Toriyama himself admitted that he planned to get rid of Goku forever, but explains why he ended up not going through with iit.
Son Goku, the protagonist of Dragon Ball, Dragon Ball Z, GT, Super and Daima, was not going to enjoy the journey that he eventually had in the saga. Akira Toriyama, its creator, planned to put an end to it permanently, but the idea did not materialize, as revealed in a 1995 guide (via Screen Rant). The creative’s intention was for Son Gohan, Kakarot’s son, to replace him as Earth’s hero.
“I intended to put Gohan in the leading role… It didn’t work out. I felt that compared to Goku, he was ultimately not suited for the part,” he said.
The threat of Cell and the fate of Goku
In the Cell arc, Goku and Gohan undergo harsh training in the Hyperbolic Time Chamber. The protagonist’s goal is for his son to reach his maximum potential, because he knows that a spectacular power resides within him. The villain makes the mistake of making him angry and ends up experiencing the consequences firsthand. He transforms into Super Saiyan 2 and unleashes enormous power.
The problem with Super Saiyans is pride. Upon transforming, Gohan becomes arrogant and belittles a desperate Cell, who, knowing that his defeat is near, prefers to immolate himself and wipe out all life on Earth. That’s when Goku reacts, with Gohan in tears, and sacrifices himself for everyone else. It could have been his end in Dragon Ball, but it is not: the son, in a desperate attempt, launches a Kame-Hame Ha and his father helps him from the Afterlife. The monster dies and peace returns. And then...
A few years later, Goku returns with a one-day leave to participate in the Great Martial Arts Tournament. We already know the rest of the story: a reunion, the monster Buu, and the resurrection of the character.
Toei Animation just announced Dragon Ball Daima, and new canon anime in which Goku and Vegeta will be children again.