Marlowe89 wrote:
Because destroying the universe would completely go against Zamasu's interests and goals.
So would destroying the galaxy, since destroying the planet would work fine as Frieza has shown in RoF. And right before he said he would destroy the galaxy he said he was through with this universe, soooo I don't think what you are saying is the case.
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And on top of that when Zamasu charges up to destroy the galaxy Trunks was amazed at that amount of power.
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He wasn't interested in obliterating the universe, he specifically wanted to cleanse it of mortal life instead. He threatened Goku's galaxy as a last resort because he was at a boiling point, deemed them a major threat and wanted to ensure their erasure by any means necessary. It might have been "overkill", but I really don't think there's any more to it than that.
I really don't see why Goku would care that much about the galaxy and there was no mention of Goku being worried about the galaxy and he said he was through with the universe.
Narratively, the whole point of Elder Kai's statement was obviously to provide an indication of Super Saiyan God's strength. There's no reason not to take this dialogue at face value; he literally said that they had the power to destroy the universe and the entire authorial purpose was to showcase to the reader the scale that we're operating at for this brand new realm of power.
It's all pretty simple. The lower end of the "Realm of the Gods" can destroy the universe after just two or three shots, whereas the higher end can destroy it in one. Galaxy level as a maximum endpoint is pretty damn irrelevant in comparison.
The thing is the elder kai never once said that Goku could one shot the universe, he just said the power is a threat to the universe and I'm pretty sure he said something extremely similar when they fought Buu. And he never said they would destroy the universe in a few shots in the manga, and you can't just say they have the exact same level of power, especially when Goku never absorbed god ki in the manga and Trunks never went SSR.
Also in the anime Elder Kai said Beerus can't survive a galaxy bust, so if you want to take his words at 100% face value Beerus' durability is less than universe level, which doesn't make sense if SSG is universe level.