Back in Dragon Ball Z, Gohan initially had to be the trainer of Trunks when the Z warriors had to confront the androids created by Dr. Gero. But it all ended very badly for the Z warriors, so there was only one way to make things a little better. Trunks, who became an adult, had to travel back in time to warn the Z warriors of the arrival of the androids. In this way, at least one timeline could have been saved.
Knowing about the evil threat that was coming a few years later, Goku and the gang had much more time to train and prepare. While even Future Trunks chose to stay around so that he could give a helping hand against the diabolical machine, there was no such thing as a fusion at that time. It was only later in the Buu Saga that the concept of the fusion between two warriors was introduced. But many fans would have been eager to see a fusion between Gohan and Trunks, the sons of Goku and Vegeta, respectively.
Super Dragon Ball Heroes brings Gohanks to the fighting scene
According to ScreenRant.com, chapter 8 of Super Dragon Ball Heroes: Dark Demon Realm Mission brings another character to the scene: Gohanks. As you’ve already guessed, he is none other than the fused form of Gohan and Xeno Trunks.
The two Saiyans decided to use the technique in order to fight Lord Slug and the Demon Gods. The villains seem to be vastly superior in terms of power, so there seems to be no other way of having a chance against them than to use the Fusion Dance.
Goku and Vegeta were the first Dragon Ball characters to use the Fusion Dance. They used it against Majin Buu, becoming Vegito. Later on, the two beloved Saiyans used another form of fusion to give birth to Gogeta.