Not a huge fan of Neo/Acacia, for the same reason that I don't like Madara and Aizen. If you're going to have someone beating (or, in this case, killing off) the strongest characters in the series, I feel like they should at least struggle for it. That way, it's more believable when the main character (who almost always has the most straightforward power set of the entire cast) manages to beat them in the end.
Take Blackbeard for example. Sure, he beat Ace and somehow has the ability to use more than one Devil Fruit at once, but his main fruit has clear drawbacks, in addition to the problems that every Devil Fruit user has to deal with. Sure, he's powerful, but it still seems like it's possible for Luffy to beat him.
Otherwise, the only way that the main characters can win would be if the author pulled a method of doing so out of nowhere, like Ichigo getting stabbed in his mind for three months/an hour and somehow becoming temporarily all-powerful because of it.
But in this case Jirou did the same thing to him. It wasn't one sided. It seems like if he used knocking on his mouth too, Jirou would seal him. There was a panel where 'he released million knockin' but we don't that would have been possible with this mouth knocked. So this is what happens with this level of fight. It's kinda one who gets the first shot wins and you don't ever get to make any mistakes. Remember how Jirou lost his head, then almost win?
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I liked how Jirou went out. It was quick but only because he underestimated Neo, an opponent who knew all his techniques and used it against him. It had to go down like this because unlike Don Slime, Jirou had the power to defeat Neo. This was the only way to have Jirou lose.
Not entirely convinced Acacia's feelings were all fake in the past, at least not in the very beginning.
That matter is kind of complicated. Maybe it's Neo's appettite runing over Acacia's consciousness. But it really doesn't seem to be like that. Ichiryuu too was talking about Acacia as if he was planning all things out. Remember when he said about 'plant of darkness or evil was you Midora?'. So he knew Acacia saw them only as plot devices. Which still we don't know how they were necessary though. And we never got to learn what Midora's darkness accomplished.