Several years ago, an incident happened that shook the world and placed her in the hearts of the supernatural.
A prophecy was told about a savior whose reign will begin and end with mass death. Despite the calamity, she would bring, everything after that would experience several long centuries of peace.
She would be the cause of the first war against the supernatural realm. The prophecy was relayed from one person to another until it became common knowledge for all.
Fear was a powerful tool that united several nations. Species that were normally at war agreed on one thing for the first thing.
Once the person is born, they will get rid of her before she grows. This was because as per the prophecy, only she could take her life after she turned eighteen.
No matter who and what powers they used, nothing would kill her. That was to say, she would be immortal unless she decides that she doesn't want it.