Now that the episode is out, the storyline continues with Sasuke making clear his intension of why he came back and helped seal Kaguya. Well it is like him though to spoil the profound victory and joy. You see in Naruto we have no villains but people like Sasuke who just come up with their own crazy ideas. Like now he wants to eliminate the 5 Kage, tailed beasts and Naruto. Even pain and Madara had similar ideas about humanity and this just makes them the antagonists instead of villains.
So Sasuke’s revolution is all about destroying that which he deemed unfit in the world he wanted to create. As he said, Hokage carries a different meaning to him from that which everyone else knows. So he immediately made his moves, which did not catch Hagoromo by surprise as he expected such an outcome.
He put all of the tailed beasts in a genjutsu and then used his Chibaku tensei to temporarily seal them. Of course Naruto would not like this and he moves to confront Sasuke. Ready for anything that could happens Naruto urges him to release them. But Sasuke realized that the only way to proceed with his plans is through a fight.