When he realizes it's Obito who was the masked man and is currently being used on the battlefield to revive Madara

He's either gonna be disappointed or guilty.
When he realizes it's Obito who was the masked man and is currently being used on the battlefield to revive Madara
I also started to think to myself, that he was definitely surprised that it was Obito, but I also think that he noticed something else. for example, that Obito was being controlled and he is going to try and stop him from doing whatever it is he is doing, because keep in mind that Obito may still have the seal on his back.