SPOILERS
I sacrificed Jae twice, the first time he didn't go to the Never (it rejected him for some reason) and Reina came back online, the second time he was claimed and Reina didn't come back. Did the same for Amelia, first time she was claimed but Reina didn't return, the second time was the same but Reina did return.
does your responses to Reina and/or the chosen sacrifice determine what'll happen? is there really a way to sacrifice yourself?