[action]
[The shock was understandable, after all this whole story took him a while to believe too especially with all the things Itachi had done to ensure he'd stayed on the path to kill him for revenge.
Sasuke hesitates for a moment based on the reaction from his younger self]
It's a long story, it started with the Kyuubi attack on the village. The elders that the Uchiha were responsible for it because our sharingan are the only thing that can control it. Even though the cause wasn't known, they became suspicious and distrusting of the clan and thought they were going to start a rebellion against the village.
[He just stops for a moment, he'll just say this slowly just in case the other wants him to stop, but overall he knew it was a lot to take in. Even saying it aloud, it was hard for him too]