When Gohan reaches Super Saiyan 4 in Super Dragon Ball Heroes, his strength is so potent it appears to have completely surpassed Super Saiyan 4 Gogeta, a character who at one point was thought to be the strongest fighter in the entire franchise. As far as Saiyans go, Gohan has always been in the upper echelon of fighters. Ever since he was a child, Gohan has shown astounding potential from the power that surges within him whenever his emotions run out of control. As Gohan grew older, this power would wax and wane as the plot demanded, but hints of his prior destructive capacity still remained. In Super Dragon Ball Heroes: Dark Demon Realm Mission, Gohan’s full power returns with the appearance of his most powerful form yet.
In chapter 13 of Super Dragon Ball Heroes: Dark Demon Realm Mission, the Demon God Shroom is busy chasing Pan and Gohan in a damaged part of history. The Time Patrol are currently fighting in the Dragon Ball GT era, sometime during the battle between Super Saiyan 4 Gogeta and Omega Shenron. Gohan himself feels as though he is outclassed by Shroom, who uses a deadly technique involving reaping one’s soul. In order to make up the distance between them, Gohan allows himself to transform into a Great Ape. He is able to quickly gain control of the form, which is the catalyst for becoming a Super Saiyan 4.
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Gohan arrives on the scene as a Super Saiyan 4, controlling the transformation in what seems like record time. Though both Goku and Vegeta rampaged shortly before becoming Super Saiyan 4, Gohan’s transformation is much more instantaneous. Additionally, after he becomes a Super Saiyan 4, Gohan is easily able to swat the Demon God
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