Kakashi gave that implication before knowing Zabuza could make the mist thicker. Pay attention that at that time the mist wasn't even thick enough to stop Kakashi in copying his jutsus
Doesn't matter how thick the mist was at that time - better vision means better vision. When a mastered Sharingan works better inside thin mist, it also works better inside thick mist. Logical, isn't it? Kakashi was, by the way, still able to block a great number of Shuriken at once [
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], which was ascribed to his Sharingan.
Rinnegan(Sharingan's evolution) couldn't see through Mei's mist. There is no reason to believe Itachi could
Which I never claimed.
The crow strategy is what i was waiting for, but don't forget one thing. The time the crows gather to give away Zabuza's position, he can change his location anytime. It's not like he would remain in the same place while fighting.
Neither do the birds; they can simply use their claws to cling to Zabuza. Not to mention that moving is easier said than done while being attacked by a swarm of crows; already a few of them were enough to temporarily stop even EMS Sasuke, whose level is far above Zabuza's. Should he try to move regardless, he'll just run into more of them - you get the idea. Using the crows, Itachi can lay a tight surveillance web working similar to Gaara's sensory sand. Gathering isn't even necessary for them to give away Zabuza's position; if those who discovered him first start cawing, Itachi will know his position immediately. And so will nearby crows, resulting in more and more of them swarming Zabuza. In conclusion, moving is not much of an option. Even a few seconds are enough, considering Itachi's vast fighting pace.
Not to mention that if Zabuza were to use water clones, this strategy won't work considering the crows would never identify the real with the original
Wrong. It doesn't work as perfectly, but it still does in general. If there is more than one Zabuza, the crows will split up; Itachi will be aware of the fact that Zabuza has cloned. He simply replies using his own Mizu Bunshin to go after each one. The crows might even be enough to dispose of the Mizu Bunshin themselves, considering how weak they are; Genin Sasuke defeated 10 of them single-handedly.
In the end, that strategy isn't getting Zabuza anywhere, considering he still won't be able to approach Itachi undetected. Nor is it within the thread's stipulations, considering you determined him to fight like he did against Kakashi. Since he's unaware of Itachi's Kuchiyose, he'd have no reason to actually use Mizu Bunshin; he'd arrogantly believe in his counter to Itachi's Sharingan. If Itachi was to summon the crows while Zabuza was still forming the seals for Kirigakure no Jutsu, he'd not even get a chance to create Bunshin.
Like i've said as well, in the mist the reaction speed is slower.
Don't take that statement out of context; Kakashi said his reactions were hampered because he was unable to see. In conclusion, the same applies to Zabuza, whose eyes are constantly closed. After all, his sense of hearing does not replace his vision. Jiraiya implied that even sensory types are unable to perfectly defend against attacks they're unable to see [
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]. To put it in a nutshell, I don't see your point.
Zabuza on the other side like you said can pinpoint locations via sound, and fight accurately. It's not as if as well the crows don't have different sounds than ninja movements. Zabuza could perfectly identify Kakashi's movements to Sakura's/Gato's
As I've pointed out above, Zabuza isn't fighting as accurately as regular, either. Like I explained various times already, he's not approaching Itachi without being noticed. Your second remark isn't applicable to this situation, considering he roughly knew Sakura's and Gatou's position. Itachi's sounds, if he makes any at all, aren't mixed with those of the crows, they're completely masked by them.
Itachi won't be capable to perform his combos to defeat Zabuza in the mist as well as he normally does because of the pressure of fighting in the mist while not knowing the real location of the opponent/being attacked from everyside without actually knowing said location.
Weak point, considering Itachi is trained to stay calm even in the most bizzare situations [
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]. Thanks to the crows, he
will know where Zabuza attacks from; as soon as he has been located, no fancy combinations are needed. Not to mention that Itachi's swift Bunshin feints, instand handseals and fast speed work as perfectly inside the mist as they do outside.