Well for starters, in Black's case his ki was Zamasu's and not Goku's, while for Ginyu he still had Goku's ki. Vegeta even commented that it felt like Kakarot.

Super Saiyan Rose might be the effects of "true" God-ki that Kaioshins possess, rather than the Saiyan version of it.

I still believe that Rose is Black's variation of Blue. After Zamasu gained Goku's body, he should be able to access Goku's other transformations too.

He probably should.

i think so too. this is how a kaioshin can become in a saiyan body or something like that.

+ he becomes stronger with every fight in gokus body

but i think that the immortal zamasu is still stronger than SSR black.

Ok dude, watch episode 63.

BEST SUPER EPISODE EVER. ONE OF THE BEST IN THE ENTIRE FRANCHISE. Not a single dull moment.

As fanfiction-y as the idea is, I gotta admit Merged Zamasu looks really cool.

I really want a GodTube page to be created :3

@Stryzzar and this is like fan fiction done right in the best way possible.

I'm just happy Vegeta accomplished something other than being the deus ex machina to save Goku and Trunks in this saga. I mean, he's not only matching Black, so far he's actually winning.

And I've been waiting for an enemy to use a form of fusion. Granted, now it means the only way Goku and Vegeta are winning is the Mafuba. While I could believe Vegito could beat Fused Zamasu, I don't believe Gogeta would be able to in limited time. 

Honestly, though Gowasu *and* Universe 7 Kaioshin staying behind to watch the fight? Bad idea. If the old Kaioshin doesn't count, Beerus is dead and Whis apparently deactivates if that Kaioshin gets killed.

How come? Both Goku and Vegeta treat Zamasu as something of a nuisance because of his immortality, and in Black and Zamasu's strategies Black is the sword and Zamasu is the shield. Zamasu is definitely strong, but Trunks can match him with just the regular SSJ2 form.