I have a theory:
Whatever plan the MoM has it could entail Worldline jumping. There's a possibility that the Power of Waking could be used to jump Worldlines. That would explain why he disappeared during KHx and we see him in the Secret Ending, meaning that he could have died.
This is where Yozora comes into play. We know that the ultimate price for the overuse of the Power of Waking is death. Something tells me that Yozora's role in the Master's plan is to come and pick him up whenever he dies in order to keep abusing from the Power of Waking without any sort of permanent death.
Like a 1up.
Whatever plan the MoM has it could entail Worldline jumping. There's a possibility that the Power of Waking could be used to jump Worldlines. That would explain why he disappeared during KHx and we see him in the Secret Ending, meaning that he could have died.
This is where Yozora comes into play. We know that the ultimate price for the overuse of the Power of Waking is death. Something tells me that Yozora's role in the Master's plan is to come and pick him up whenever he dies in order to keep abusing from the Power of Waking without any sort of permanent death.
Like a 1up.