When Itachi was given the order to hunt down the kyuubi jinchuuriki, who is also his brother´s teammate, he was mentally prepared to meet his brother. As fate would have it, Sasuke was indeed present. However, Itachi is currently both disappointed and proud of his brother in this moment. He is disappointed, because Sasuke made a very loud attack on somebody who was FAR beyond his level and he (Sasuke) knows this. That was both foolish and dangerous in the extreme and Itachi easily stopped the attack.
On the other hand, Sasuke have mastered chidori and have a fine grasp of it. It speaks well of his skills and potential. There is one thing however, Itachi cannot ignore, and that is the cursed mark on his neck. He narrowed his eyes and nearly glared at it while cursing Orochimaru in his mind. Have many dark thoughts about the sneak sage, but suddenly ´I have an idea´ and the rouge genius smirked in his mind as is brother struggled to get out of his grasp.
"So brother, this was your grand attack on me? You are pathetic still, you may have learn a useful jutsu, but clearly still too foolish and arrogant to use it properly" The silent death glare from Sasuke was his only response. Itachi made a quick glance towards Jiraiya. The sage was content to watch for now, properly to avoid risking killing the genin in the fight. So Itachi continued.
"I see that Orochimaru have given you one of his curse marks. It is fitting for a pathetic weak worm like him to seek you out for your sharingan. In fact, his ambush on me was just as weak and worthless as your own" That got a reaction from his audience. Jiraiya narrowed his eyes and clearly was thinking about the implications. Sasuke was in shock, but Uzumaki´s reaction was a blessing in disguise.
"Wait, you beat Orochimaru?" The blond jinchuuriki asked and gave Itachi the perfect reason to explain what happen that day, but Kisame beat him to it. "Orochimaru was part of our organization before he attacked Itachi, but he had to be saved by his subordinates after he was beaten" the missing-nin from the mist explained, then Itachi continued on "Indeed and I was uninjured, just like from your attack Sasuke. Now brother…" Itachi stared into Sasukes eyes and mentally said sorry for what was about to happen. "You clearly still…LACK hatred"
Sasuke has been in turmoil ever since his encounter with his brother. The fact that his best friend and teammate is caching up to him fast also pisses him off and may soon leave him behind. He needed more power, FAR more power. The problem was he did not know where or how to find it.
´Who do I turn too? Kakashi and the other jounin teachers know many jutsus but they either cannot or will not teach me! There is no way in hell they would let me read the Scroll of Seals too´ such dark thoughts clouded his mind, combine with his brother´s words that he still did not have enough hatred and the clear fact that his brother was still far more powerful, were becoming increasingly normal for the trouble avenger. However, not now, as he has just been ambushed and defeated by the sound four despite his best efforts. Giving him a speech about all the power Orochimaru would give him. Sasuke while were tempted to snort during their little speech. While the offer would be tempting, there was just one problem namely… ´Orochimaru could not even injure my damn brother, despite ambushing him! Why should I seek power from one, who cannot even harm Itachi?´ Sasuke thought venomously, he was not foolish enough to say that out loud to the snake´s minions as he was still at their mercy. But, like his brother Sasuke could adept and get ideas on the fly. Sasuke smirked as he got an idea how to get more power, he just need a day.
"Tomorrow" The Uchiha said, staring into the eyes of the two-headed sound-nin. Sakon and Ukon raised their eyebrows at that statement before asking "Why tomorrow and not tonight?", Sasuke thinking quickly came with an explanation that would hopefully not rise suspicion and get him kidnaped.
"Hatake Kakashi have a few Uchiha scrolls in his possession, he borrowed them some time ago to see what jutsus and technics he thought I should learn first and expanded his own arsenal of abilities. I need them before I go to Orochimaru" Sasuke was lying now, as there were no way in hell, he let anybody near his clan's jutsus, but they did not need to know that. They gave one another a look before the red head answered "and what stops you from selling us out to Konoha?" The avenger glared at her, as she was dangerously close what he actually wanted to do. But, he was not stupid and had an answer at the ready "Nothing, just like I have no proof Orochimaru would not just rip my eyes out or at least start experiment on me, the second he gets his hands on me" The last Uchiha answered while he still glares at the red head.
There was a silence between them now. Thinking what has been said until now, Sakon and Ukon came to a decision "Fine, tomorrow night, here same time, those jutsus better be good Uchiha as we a putting our necks out for you by risking Oruchimaru-sama´s disfavored" and then they were gone.
Sasuke first went home to make sure they did not follow him. After a bit of time he went to the Hokage who he learned was in the hospital to operate on Rock Lee.
Then he arrived and found her washing hands, he was noticed quickly by the slug sage and she started "Brat, your friend is in that room, I got no time for you right now. If you want to speak to me do it tomorrow" she was already on the way to the nearby door as she said this, however, he needed to speak to her and he needed to be polite too, which annoys him. "Hokage-sama, I am not here for Lee, I need to speak to you as I was attack by some of Orochimaru´s servants and giving the offer to defect" he said and that got her very still, before turning around fast "tell me everything" she ordered and so he did.
She called an emergency meeting shortly afterwards, which included several jounin, the ANBU commander, some of the clan heads, the elders and Ibiki, as they were short on time and many were on missions they could not have a full council. There he would repeat what had happen and the faces of all who are present was grim. Tsunade started "I suppose it was too much to hope that Orochimaru would change focus to another project so soon. Uchiha-san did well to warn us. Still that does leave the clear problem that we still have a security breach, as the sound nin can get in and out again without raising the alarms or be spotted by patrols" she finished and looked at the Nara clan head Nara Shikaku, who followed up right with a plan. "We can use this opportunity to capture them and interrogate them when they show up to the meeting and from there hopefully find whatever remaining holes in our defense and get more information about Orochimaru´s operations. Still we should also prepare for more sound agents, as they may not trust Uchiha-san and get support in case of ambush" he finishes and takes a look at the other, who responds by nodding as the real discussion started and the occasional debate. In the Meantime, Sasuke stood and waited in mostly silence, save to answer a few questions in regards to the sound four, this state of affairs annoyed the last Uchiha as he could not raise his own proposal. Eventually as the debate ended and the plan for the ambush was set, he got his shot.
"I have a request Hokage-sama" He says while still standing, this of course got the council attention focused entirely on him. "Yes what is?" Tsuande asks curious of what is, although it is clear she was very tired. Sasuske took a deep breath before continuing, "I request more personalized training so as to better defend myself against future attacks. As it is clear that Orochimaru will target me for my sharingan and will probably continue to do so after the sound four has been dealt with" Now to be sure, no one among the council was really fooled, that it is not the true reason for the request. They all knew he just wanted more power to kill Itachi, that said however, his argument is by itself also not wrong and it would be foolish to ignore the threat. Especially the potential a sharingan wielding Orochimaru would pose to the village. As such Tsunade in response "You request is accepted, however, we will have to talk about a proper teacher for you and that will have to wait until this situation has been dealt with and I had a talk with somebody else. Now is there something else that needs to be brought up or any last minute questions?" she asks as she looks carefully over the assembly, she briefly notes that the Uchiha was looking satisfied with her response. As there were noting more, the meeting was dismissed, as some prepared to sleep and others started their own preparations for the ambush.
As expected, the ambush was a success, despite the surprising presences of a surviving member of the Kaguya clan and a few chuuni sound nin. However the sound four and their allies was no match for the gathering jounin and ANBU, that included the Hokage herself who wanted to make sure that they would no escape or die needlessly. Despite the one sided beat down (The Hokage handled the sound-nin herself and the rest of the just watched from the sidelines. Tsunade denied repeatedly that she did this just because she was just bitter over not having time to drink some alcohol in one of her secret stashes, because of the sound ninjas´ actions and this was just revenge).
As such only the Kaguya died, because of his bad health could not take the punishment from the (totally not) angry Hokage. The week after the ambush, Sasuke was informed that team 7 would be temporary dissolved, as Tsunade would train Sakura and Jiraiya took Naruto with him on his journey. As for Sasuke himself, he was rather bitter over his teammates would be trained by sannin, but he did personalized training from Kakashi and would join other teams to training from time to time and as such chose not to complain (too much).
As for Orochimaru, he were forced to propone his attempts against Sasuke as a mix of Konoha attacks, using information gained from the sound four distracted him and Uchiha Itachi threatening to kill him if he ever got close to Sasuke ever again. However, the Uchiha kinslayer did eventually kill the snake sannin after he got a little too cocky and tried again after a few years later.
Sasuke however did however grow during the years in Konoha, both as a ninja and as a person. He never came to hate Konoha, even then Tobi revealed the truth after finally defeating Itachi, but he settled to just focus his hated on the elders and used Danzo´s own actions as an excuse to kill him and the two others with the help of rest of konoha 12. Eventually and found something else in life besides hatred, revenge and a hunger for power.
Author Notes: Hope you like my story, also please forgive the spelling and the grammar, as I am not an native english speaker and have dyslexia. Also I am new to this so useful and constructive critisism would be appreciated.
Update: Thank you very much for reading.
Also to answer Danish78 and his quite spot on critique. I did in the start wanted to do something like what you suggests, the problem is however, it endded up being far too ambitious for somebody of my current skills (or more lack off). That is also why the ending is like it is now, as I simple was not sure how to properly write a better one.
So, in the end this was more for the concept and fun, bot the best combination for writting an one shot story I know. Still My idea originale was this, While Kakashi is not as powerful as Orochimaru, he does have 1) sharingan and could learn/teach more of it with Sasuke and they both become stronger for this. 2) in my own headcanon kakashi should know a mountain worth of different jutsus, this alongside traning with other jounin and their teams that would get Sasuke a big areasnal and many tools to use. This should quite practical give Sasuke a big advantage, as in canon most characters just the use same attacks and jutsus over and over again. So having many jutsus and actually use them is a big advantage.
Also for Danzo and the Elders, I admiteetly forgot to write in that he had allies with him then he did this, my bad, also Danzo and the elders did the massacre without approvel and Danzo did kill Shisui for his own gain, before latter could stop the coup. So what Danzo and the elders did was very much treason and Sasuke wherefor could get support to kill them. I also did not really think of the plot all the way to Kaguya. Also in regards to Itachi´s "genius" I do quite agree. This here was just him trying to protect Sasuke from Orochimaru, as he had no real influence to stop the snake sage form stealing Sasuke´s eyes, save force and trickery. As for Chidor, again I agree that it is not a good assassination attack, unless you can speed blitz the target.
At somepoint in the future I would properly rewrite this and make a better one short or even make it into a small story, that is then I have more experiance and skills to do it.
Also thanks again for reading.