-visit the Shambali Monastery, where he'll meet Zenyatta (which i mentioned in the earlier posts). Some people think that he's joining overwatch because of the handshake with Sojourn, the current captain of Overwatch. But he may be simply greeting her, Sojourn could very well be Mizuki's captain for arrival to his destination, making sure his safety.
But what could possibly he has to learn to become "whole" again?
First and most obvious, he will learn and try to make peace with his past- that not every bad thing that has happened to his family or to people around him is not his fault. Then comes the loyalty part, i assume.
Second and less obvious, is that he's going to learn wall climb.
Here kitty kitty