Vivian pov:
As Valid said the only other way to defeat the demon king is to sacrifice our mana. I am fine with sacrificing myself but I couldn't do that to them.
So there is only one option left and it is to sacrifice my life but I won't be doing it I already promised Cindy that I will not make the same mistake.
When Cindy made me promised not to make the same mistake she means that I should end the demon king once and for all and to not sacrifice myself.
Cindy was fine with sacrificing herself because she has no one else to go home to but I am different.
I have family and friends waiting for me to come home. I have to come home. So no matter what happen I will make sure that no one dies.
I will make that we get out of this alive. All of us. I can't guarantee that everyone will live because I am not a saint nor a God.