This raises another question: why is anyone still with Akatsuki?
SPOILERS
They all seem to be in it for personal gain, whether it is monetary gain, glory, or power. But the main goal of Akatsuki
is to gain control of all nine chakra demons. Each member of Akatsuki is strong enough to EASILY take down a
village's Kage (except maybe Tobi... I still want to see what he has up his sleeve!), and having possession of a
demon would make them unstoppable. It is this promise of a mutual gain of power that allows Akatsuki members to
cooperate with one another.
So why is Itachi still with the gang? He killed his best friend for power (Mangekyou), and then killed his entire clan
to test that power. I believe that when Akatsuki gets all nine demons, the members of Akatsuki will inevitably turn on
one another until only one person has all nine demons (I'm not sure if there's any evidence saying this is
even possible) and become a god.
That's where Sasuke comes in. If Sasuke can become strong enough to take on Itachi, this will allow him to extend
his bloodline powers even more... or perhaps Sasuke can be manipulated into taking out the other Akatsuki members for
him! Perhaps Sasuke is the key for Itachi to be the strongest in the world.
This... is one big guess, but I say that Itachi is pure evil, one who is trying to gain as much power as possible.
