[A/N: Wow, this is really angsty. I never really tried writing angst before, but I guess if I feel like crying in a corner now then it worked...]

...

In one world, Sasuke eagerly follows his older brother everywhere, begging for his attention.

In one world, Sasuke stares at the blood dripping from his brother's sword and wonders why why why?

In one world, Sasuke gives up everything for power and vengeance.

In another world, everything is different.

In another world, Sasuke is born first.

…

In another world, Sasuke stares down at the tiny little creature he has just been informed is his baby brother. "His name is Itachi," his mother says.

"He doesn't look like a weasel," Sasuke replies, touching the baby's face as gently as a five-year-old can, and mother laughs.

…

Father is clearly delighted when Itachi turns out to be a prodigy. Sasuke is an entirely adequate child, but his father had always been disappointed that he wasn't as extraordinary as his slightly older cousin Shisui.

Sasuke often comes home from training with his genin team to find his younger brother throwing kunai and shuriken at targets, each hitting perfectly where they are aimed. Itachi already has the Sharingan, even though he is only four, and Sasuke is a little bit jealous.

He decides he isn't jealous any more when he sees that Itachi's hands are bleeding as he throws again.

…

It is a bit strange, Sasuke thinks, that he finds himself so often trying to get his younger brother to pay attention to him. Shouldn't it be the other way around? But then Itachi has always been different. And there is something about him that worries Sasuke, a voice telling Sasuke that a five-year-old shouldn't be acting this blank and grown-up.

As their father pushes Itachi more and more, it becomes harder to distract him from his training, but Sasuke still manages to get him to a dango stand a few times.

…

Itachi is six when things start to go wrong. Sasuke is a chuunin now, and a bit more than an entirely adequate shinobi. He isn't sure what to expect when the Hokage has him brought in for a secret meeting.

Hearing about the planned coup isn't surprising to him. His father has always wanted power. But there must be some kind of solution besides extreme measures, there has to be.

He only has a few months to make a decision.

Itachi is still as blank as ever, but his training has become even more intense.

Sasuke won't allow the Uchiha to ruin any more children.

…

He is actually a little surprised at how easy everything was. He did have the element of surprise (and the Mangekyou, don't forget Shisui lying in the river, he could be only sleeping if it weren't for the water covering his face), but still, a chuunin destroying the entire Uchiha clan?

Sasuke stares absently down at the small puddle of blood dripping off his sword. Then the door opens.

Itachi is surprisingly calm as he looks down at the bodies on the floor. His blank mask never slips. "You killed them, aniki" he says.

"Yes." Sasuke had imagined this conversation, but nothing like this.

"Why?"

"To test my capacity." Even to Sasuke it sounds like a lie.

"Mother doesn't like it when you lie, aniki."

A few seconds later (hours and hours a day had never seemed so long) Itachi collapsed, exhausted from screaming. Sasuke looked down at him, torn between satisfaction that Itachi now realized the severity of the situation and horror that he had just done something like that to his own brother.

"When you have the same eyes as me…"

…

After that, the Hokage decides that Itachi should stay in the Academy for a few more years, 'In case Sasuke comes back for him," he says, but he means 'in case Itachi snaps'.

Itachi graduates when he is twelve, and is promptly assigned to a genin team with the Kyuubi container (this was supposed to be a secret, but Itachi had known for years) and a pink-haired girl who was mediocre enough that he knew nothing about her.

"So, tell me about yourselves," their teacher asks. "Likes, dislikes, dreams, whatever."

Itachi doesn't care about their dithering about ramen and boys (he doesn't care about anything), but he listens anyway. He might need the information later.

"And you?"

Itachi shrugs. "I like nothing. I dislike little more. I have no dreams. My only goal is to kill my brother."

Sakura gasps. "But why?"

"He expects it of me."

…

After a few months, Kakashi enters them in the Chuunin Exams.

Itachi's statement about not liking or disliking anything seems to be true, as Kakashi has yet to see him display any emotion at all, even after Orochimaru's Curse Seal.

Kakashi teaches him Chidori, in the hopes that its rushing surging power will bring some sort of spark into those blank blank eyes. It doesn't work.

…

Itachi's illness begins to show for the first time after the fight with Gaara. At first, the nurses think it's only strain from chakra use, but it quickly becomes clear that it is much, much worse than that.

When he isn't anywhere to be found a few weeks later, Naruto and Sakura go to look for him, thinking nothing of it. He has become even more withdrawn lately, barely speaking to them and being almost mechanical when he spars.

Kakashi finds the two a few hours after that. Sakura is kneeling by Naruto's side, desperately trying to stop the flow of blood from a gaping wound in his chest.

Itachi's name is put in the bingo books the next day.

…

No one sees any trace of him for months. Sakura is devastated by his betrayal, although Naruto seems to understand, in a way.

Then a report comes in that Sasuke was spotted in the north of Fire Country. Naruto and Sakura immediately volunteer to go after him, knowing that Itachi couldn't be far away. They don't go alone, of course, their friends refuse to allow it.

In the end, it is Kakashi and a motley group of genin that find Sasuke lying dead amidst the ruins of a stone fortress.

No one is really surprised when Itachi's body is found only a short distance away. He looks much more peaceful now, almost content.

…

The brothers are buried side by side.