I bet it's their world GM that send kaname in the future since he decided to separate him from the other when sending the group in oni land back to earth. And I'm sure he won't separate shuka from him too much or her madness will be over the top, well we will see it in this future, heck I'm sure a lot of raven will die before GM sending kaname back.
remember survival island with gorilla it was a possible future and they just got send back (with some islander) when event was over