Disclaimer: I don't own Naruto.
A/N: Follows the manga up until the timeskip.
Sasuke could barely feel his body anymore. He knew that he had exhausted his chakra a long while back, but his fear had driven him onward, and his bloody hands and knees were evidence of just how strong that fear was. For two and a half years he had aided and abetted the doings of the missing-nin Orochimaru, and for two and a half years he had trained under the dark Sannin, gaining the power that he had once so desperately sought. Now, years older and much wiser, he had done what he had known all along that he must one day do. He had used what the Sannin had taught him against him, and he had won.
Or so he had thought. There was, after all, a reason that he was now half dead at the gates of Konoha.
xXx
He had stripped himself of the garb of one of Orochimaru's henchmen and donned the clothes that he hadn't worn in years; the high collared shirt and white shorts felt strange on his body. The barely fit, but they were all he had. His other clothes, after all, were spattered in the blood of his sensei.
Sasuke smirked. "Former sensei," he mentally chided himself. After all, there was no way that Orochimaru could have survived the attacks that Sasuke had leveled upon him, and no Sound-nin would dare come after the shinobi that had killed their leader. He was safe, and he would take his time in returning to Konohagakure.
The thought of the Village Hidden in the Leaves brought an odd weight to his chest, and a flood of something that could only be called guilt. He had betrayed everyone he knew, everyone he loved—though there were few—in his desire for enough power to kill his brother. He had no way of knowing if they would take him back now, but the village drew him. It's sunny skies and perpetual warmth were in such stark contrast to Otogakure, where all was dark and dank and chill—where he had never been happy.
Sasuke hung his head a little, knowing that he could very well be exiled forever, knowing very well that he could also be killed on sight. He also knew that those he had loved—those he still loved—might never accept him again, that the very people that had made life bearable in his genin days might loathe him now. He couldn't blame them, but he did not regret his decision. Orochimaru had taught him much, and the love for power was still strong within him.
Going back was partly a selfish decision. He had received word that Akatsuki was after the biju, and knowing Naruto, the kyuubi vessel wouldn't stand idly by and let Itachi and his henchmen withdraw his main source of chakra. By returning to Konohagakure, Sasuke would be able to not only help protect Naruto, but ensure a chance to face off with his older brother.
"Assuming, of course, that they allow back inside the gates," he thought to himself, as he curled up for the night.
Barely an hour later, Sasuke was rudely woken by a sudden lack of oxygen. His hands flew to his throat, snatching a kunai from his leg holster on their way up, and he slashed into the smooth body of a snake.
"Snakes," he thought grimly, "Sensei's summons."
As the constriction around his throat slackened, he became aware of the creatures wrapped around his ankles, sliding up his legs, curving about his waist...he could feel their smooth, muscular bodies all around him, invisible in the darkness but perfectly tangible on his skin.
Shaken, he began stabbing wildly, sinking his kunai into as many of the creatures as he could, until he was free enough to scramble away. Then—
"Ssssasssssuke...why sssssoooo aggressssssssive? Fine way to ssssshow your appreccccciation...your sssssenssssei is disssspleassssed..."
He spun around, kunai in front of him, and met the eyes of his sensei in the body of a snake.
In one swift motion, he had hacked off the snake's head. In another, he was on his feet and sprinting for all he was worth in the direction of Konohagakure.
There was no reason that such creatures should have struck such fear into Sasuke's heart. He had trained with snakes for the past two years; they had become his own summons, they were the basis for many of his attacks. Yet the sick feeling of the creatures invading his body, writhing along his skin, and speaking to him...he was terrified. It was if Orochimaru himself had been crawling in his skin.
He refused to sleep; he refused to stop running. He had not, after all, killed his sensei—the snake summons had told him as much, and if his sensei was not dead, then Sasuke could not sleep, could not rest, could not stop.
Therefore, he channeled his chakra into a single purpose—keeping his body moving in the quickest possible manner toward his home village.
By the time he reached the gates of Konoha, Uchiha Sasuke was crawling.