Yeah... each world has its own rules regarding death, we are talking about souls here so where does the soul go after death in each world is the first problem if you want to 'resurrect' someone, and most of them end badly
Ah and some spoiler...
No, she not death, it's reason why MC can't ressurect her,she was only sealed in a curse made by the Demon King, which also sealed the Holy Lord Alexandros who inhabited her.
