Activating the Mangekyo Sharingan always required an Uchiha to take down a friend. Parents and siblings killed each other to obtain eternal visual prowess. We're both from a tainted bloodline that advanced its strength this way throughout the ages! And from the day you were born into our clan you have been unavoidably entwined with this blood soaked fate! Now come my little brother! I shall kill you to obtain my true transformation and finally be free from our clan's fate!
All S1
S1 E15Unfinished Business
Ah but the ordinary Sharingan is still a weapon and a weapon can be either strong or weak, depending on the ability of the person who is wielding it. Someone's shuriken might be taken down by a mere pebble if it's thrown by a master. The difference is in the power, the variation of strength. It means that Sasuke's skills far exceed Itachi's expectations.
Like I told you, no matter how much you use your eyes, with all of my hatred, I'll turn fantasy into reality.
Turn fantasy into reality huh? Some strong words. And let me throw them back at you now. Just a few minutes ago you saw your eyes gouged out during the Tsukuyomi. Well allow me to make that a reality.
You'll be gone with the thunder clap. [uses Kirin on Itachi]
Such power.
So did Itachi die?
It's done.
[alive] Is this the death you had imagined for me then?
Damn you! [activates his cursed seal]
If I hadn't had this I'd be dead. [activates Susanoo]
What's that?
You really have gotten stronger Sasuke. Now it's my turn. I'm going to reveal to you my final trump card, the Susanoo.
The Susanoo?
Yes the one other jutsu. Once the Tsukuyomi and Amaterasu were awakened, it also took root in this eye of mine. Sasuke, is that it for your Jutsu then? If you have anything else up your sleeve, now's your last chance to play it. The real battle's just beginning.
[on Orochimaru] Gross fellow as always, regurgitating something out of his mouth like that.
Slithering around like the snake he is.
And now your eyes are mine. I'll take my time retrieving them. [coughs blood]
Whoa what the hell?
Something's wrong with him.
[Sasuke attacks Itachi with no effect]
That Susanoo jutsu of his, it's simply repelling every single one of Sasuke's attacks.
There's no mistaking it. It's another spirit weapon. It's called the Yata mirror and it's said to deflect all things. With that and the Totsuka blade for attacking, Itachi's invincible.
They're my eyes. They're mine.
[Sasuke is defeated, but instead of killing him, a smiling Itachi pokes his forehead before dying]
No way. Is Itachi really dead?
Sasuke triumphed in the battle. Itachi Uchiha is dead. [everyone is shocked]
TTobi
What? I don't believe it! Kidding. It's just as I expected.
What? Sasuke killed him? He killed Itachi?
Sasuke is down right now too. So what's next? I think he's in pretty bad shape.
Hey, you up there! Spiky aloe guy! Tell us where Sasuke is right now!
What do you mean by aloe?
Ignore him.
[Kakashi looks at Tobi and sees his Sharingan]
TTobi
We're just going to have to finish this some other time.
TTobi
You think you know all about your older brother but you know nothing.
If you continue spouting such nonsense and lies, I'll kill you right here.
TTobi
You're not making this easy. I suppose that's only natural hearing this from a complete stranger, but what I'm telling you is the truth. Itachi did mention it, didn't he? That he wasn't alone that night, that he had an accomplice. I am Madara Uchiha. I know everything there is to know about Itachi. I suppose Itachi died without realizing that.
Shut up! None of that matters anymore! Just get out of my sight, you hear me?
TTobi
No, you listen. You need to hear this. It's your obligation. It's about the life of your brother who risked everything for the sake of the shinobi world, the Hidden Leaf Village, and most of all for you, his little brother. You will know how Itachi Uchiha lived.
TTobi
[To Sasuke after revealing the truth about Itachi] Those eyes of yours did not perceive a single truth about Itachi. You weren't able to pierce through any of the illusions he created.
[Last words, pokes Sasuke's forehead] Forgive me Sasuke, but this is it.
[in the present] We are no longer the Hebi. From this day on, this team will be the Taka. And Taka has but one goal. Our mission... [Awakens his Mangekyo Sharingan] is to destroy the Hidden Leaf.
What Itachi wanted to see and what I will see from here on out will be completely different. I can't do what Itachi wished me to. I will restore the Uchiha clan in my own way.
[of Sasuke's Mangekyo Sharingan] Those eyes of his have improved. All that's gonna do is make him even more difficult to deal with.
Oh wow Sasuke's gotten even cooler!
It's nice here. I think I'll be able to keep myself under control. I feel so calm.
Oh my sight. Light too bright. Noon already?
Only one who gets to dig me is me yo.
I'm feeling hella fine. I just wrote the phatest rhyme.
First I'm gonna float and fly like a butterfly. Then I'll sting you like a killer bee!
[To Sasuke] I won't let you die. You're a memento of Kimimaro.
These quotes come from Wikiquote's Naruto: Shippūden pages and are available under the Creative Commons Attribution-ShareAlike License.