As much as I like Itachi, I've gotta say that
Pain takes this. All six Pains vs Itachi is a lose
situation for Itachi, mostly because, as great as
he was, if all Pains attack at once they will
overwhelm him. He would have to dodge and
counter the summonings from the Animal Path
while Pain could hide away the Naraka Path
(Ressurection) inside of the chameleon to keep
it safe. Provided that he could take on all of
the summonings the Animal Path has, which
we don't even know the maximum number, he
would have to deal with long-ranged attacks
via the Asura Path (Weapons). He was shown to
possess missile attacks, and could thread them
through the fight and attack Itachi while he's
dealing with the animals. And as shown in the
Sasuke vs Danzo fight, Susano'o can be peeled
away. To have the missile attacks, the animals,
and Asura potentially rushing in with bladed
weapons, even the Yata Mirror wouldn't be
enough.
While all this happens, should Itachi try to
utilize Amaterasu, the Preta Path (Absorption)
could run around absorbing the jutsu, and
while he might be only to absorb one at a
time, whose to say they couldn't gather
together and be taken care of at once? Or if a
summoning gets his they can just be
unsummoned and summoned again (I think)
since in the fight against Jiraiya, the chameleon
was sliced apart by a water jet and
unsummoned, but is seen again later in the
manga.
This isn't including the Human Path (Soul). If it
lays one hand on Itachi, he's done. End of
discussion. Itachi's soul will have been taken
and he will die. The Human Path can be
running through the ranks, combining his own
attacks with the others and attempting to peel
apart Susano'o to get his hand in and grab
Itachi.
Now comes the real trouble, the Deva Path.
Deva could keep his distance like was his
strategy vs Naruto. Human, Asura, Animal, and
Preta would do all the fighting while he sits
back and aids when needed. If Itachi tries to
utilize the Totsuka blade, he could simply push
or pull it away, leaving Susano'o open to
attack, and could do so again a mere five
seconds later. This could also be used on the
Yata Mirror to open him up for attacks.
Even if Itachi were to take out the five other
paths, he will have exhausted most of his
chakra and potentially strained his eyes by that
point, leaving him vulnerable for Deva to come
in and finish him off. If he himself didn't use
too much chakra beforehand or kept some in
reserve, could force Itachi into a situation by
using Planetary Devastation. If Itachi can
manage to destroy it, he will have used up his
last bits of chakra and will surely be dead
following.
Now, if he hits a Tsukiyomi on one of the
Paths, I feel it wouldn't matter. The Pains
cannot feel pain. They are dead. Tsukiyomi is
intended to inflict pain and cripple an
opponent, but that cannot work on them, and
even if it does, they can be reborn from
Naraka. If he attempts to get to Nagato himself
by using it on a Path, Nagato could simply cut
off connection with that Path and remove the
link to his eyes.
As for Yasaka Magatanaba (Sorry if mispelled),
Itachi never performed this in his life that we
know of. Only when he was Edo did he use it.
Plus we don't even know what effects it has
officially. All we've seen it do is, with help,
blow up the Planetary Devastation core.
So there you have it. There are the strategic
means Pain could use to defeat Itachi. If you
have a counter then say so and don't resort to
fanboyism and just ignore all the facts I
brought up because you will be ignored.
