Guiltythree
I think Kai is going to die this nightmare. We know that they are sure not to die because their future versions are alive but if one of them were to kill himself their future version would also die. That would also explain why Kais Future version seems to be the strongest, Guilty tries to build up a reason why Kai should sacrifice himself. I mean we all know that someone is going to die in this nightmare and Kai seems to fit this role especially if his death also kills the end-boss.