Holy Black was in ultimate mode(same as hogan) the entire time until he became rose.

[Sageof7Path]

That's why he didn't transform. Just think about it. The supreme Kai of his universe probably taught him the same technique old Kai taught gohan and he used it when he stole Goku's body and had future zamasu do the ritual.

 

[uhmusddy]

Except doesn't ultimate render transformations useless

 

[Guntah]

It admittedly took me a while to realize you were talking about Gohan. For a good thirty seconds I was staring at the title honestly wondering what former professional WWE wrestler Hulk Hogan had to do with this.

 

[Natsu Shazneel]

Naruto >>>>> Goku