After the War was concluded, Tsunade retired and Kakashi Hatake became Hokage. Due to Sasuke's role, he was welcomed back in the Village. Peace did not last however, as it was clear that Sasuke was losing his grip on his sanity. He fathered two kids with Sakura, as well as had few children with Karin, and was an ANBU before he snapped. Sasuke Uchiha murdered Kakashi and fled, but not before killing several ninja including Ibiki Morino, Tsume Inuzuka, Udon, and many others. After Kakashi's death, Naruto became Hokage almost immediately after. Angered by his mentor's death, he sent word out for Sasuke's capture to the other villages.
Sasuke created a group called The Kakumei in hopes to kill all the Kages, gather all the Bijuu and reform the entire Shinobi World in his image. He traveled the world gathering members for his group. During his travels, he encountered Karin again and she gave him more children. The other Kage were attacked and Onoki, Mei Terumi and A were killed in a span of a few months. Gaara survived his attack, although with a long scar on his chest. Sasuke managed to vanish into the winds afterwards. Some say he died; others weren't too sure, given the sparse rumor here and there. It has been 22 years since the Fourth Ninja World ended and 6 years after Kakashi's assassination. There is a new generation, and it's up to you to decide how the story plays out.