she
has to be the unbreakable huntress from the storybook.
Fleming, Lord of the Underworld, coming back to take her as his mistress? Check. He's pissed at Garcia for killing his demons but I think the real reason for taking Paula is simply that she belongs to him.
He kills her and brings her back to life over and over for fun? Check. Sure, he does this to taunt Garcia as well, but the storybook mentioned this very explicitly.
She keeps trying to escape to the human world where she thinks she belongs? Check. Remember Garcia tells Johnson that he just found her in a dumpster one day and took her home. She also goes crazy violent when Garcia tries to answer a certain phone call.
All the stuff from the storybook is there. The girl is pretty fierce too, just remember the ending when she puts a knife to Garcia's throat, I'd say it's pretty obvious she's the huntress. Garcia himself curses the fact that he's fallen for the Lord of the Underworld's mistress.