You woke up in a large box. All you could remember were the words. "Protect them"

You didn't remember who had said that or why but that's what played in your head.

Eventually as the box slowly started to move upward you remembered more and more. One thing being you were a supernatural creature (of your choice)

Maybe you had to protect them from whatever was outside of the box. All you knew was that wherever you were going had to be special.