“Super Trunks” seems indicate he would get some kind of a power-up. Seeing the leaked image of episode 62, It looks like a mutation like MyBulma!Vegeta given the lack of pupils. It could be a new form too, but I guess we'll have to wait until the episode airs.
I'm most intrigued on episode 63. “The Curtain Rises” seems to suggest that Black and Zamasu will get pushed into the corner by the gang, mainly Vegeta since he's the one that is emphasized (Perhaps he'll get a power-up too?) and leaves Zamasu and Black no choice but to merge via the Potara earrings.
For episode 64 and 65. I'm going to guess Black and Zamasu will fuse at the very end of the episode and the next episode is the one where we actually gonna see him in action. I wonder how he will get defeated though, some speculate that Omni-King will appear in 65 given the episode title. Toriyama did mentioned that he will get involved in this arc, but I hope he won't just arrive and erase Merged Zamasu or something, that would be very anti-climatic. I've been enjoying this arc so far, and I hope it won't have a disappointing ending like the Golden Freeza Arc.
I would be fine with Goku defeating them through the Mafuba. Vegetto wouldn't be half-bad too, but since Merged Zamasu is presumably immortal, how will Vegetto defeat him ? Perhaps Vegetto will use the Mafuba ? We'll see, but I really think Trunks should beat the shit and kill Black, it was so satisfying when Trunks defeated the Future Androids, and him beating the shit out of Black wouldn't any different. Considering Black merged with Zamasu, chances of that happening became slim, but they could still be defused, they showed in the tournament that the Namekian Dragon Balls (At least) can defuse a merged being, so perhaps someone will use them to defuse Black and Zamasu ?
Seeing the inconsistent result of the fusion as shown by Vegetto and Kibitoshin, it's a bit hard to guess how strong Merged Zamasu will be, I can see him being on par with Beerus, but he could be stronger or as strong as the likes of Whis too.
As for Black being Present Zamasu. My guess is after he got destroyed by Beerus, Zamasu got reformed into an after life body, kills Gowasu, steals his Potara and the Time-Rings, uses the Super Dragon Balls to switch bodies with Goku, and then finds a timeline where Beerus doesn't exist to assert his plan. Elder Kaioshin proved that deities can travel into the mortal realm despite being dead, and also showed that you can be reformed into an afterlife body in the Kaioshin Realm. Perhaps Whis and co. completely forgot about these, or they don't know. Goku may know about it, but he probably didn't say anything.
This month will be very interesting.
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