Lilith

WOTD 01/11 Did you know I was human many, many thousands of years ago? I thought you were born and raised a demon in South Hell. No, I was a pure-blooded human, and because of that, I can tell that there is more to you than meets the eye. It’s almost like you were specially chosen to be there that night and be sacrificed to me. What do you mean? Katie, you are doing things no human should be able to do. There is only one reasonable explanation for that, and it scares the ever-loving shit out of me if I am honest. Katie was puzzled. She had never thought there might be something special about her. I’ve never heard of any special beings. It’s only been explained as angels and demons and humans. Nor would you have. Way back in time—I’m talking way back—there were more than just angels and demons and humans. There were those who had human natures and for all intents and purposes played the part, but they were a mixture of all three. Technically, I was told your type would never exist again. I can’t help but wonder... Katie wondered, also.

PBTD 08/3 Lilith, when she was Lucifer's wife, was also known by other names - Queen of Hell, Queen of Perdition, Queen Lilith, and Gehenna

Also, see Pandora

WOTD 06/1 LILITH CHOOSES Lilith finally chooses, and chooses to go back to Earth with Katie, as she has accepted Katie as her sister in both word and deed. In Book 5, waking the Leviathan, Katie and Pandora conquer Tiamat, the Levuathan, leaving her in Hell with Baal and Moloch. However, Pandora had to assume her original body and spirit to do so. Katie pulled her out of her body, down in Hell, and told her to make up her mind- so Lilith did. she chose Katie, sending a blizzard to kill all of the close demons, and injuring Tiamat, then opening her own portal to escape to Earth. In Hell, Lilith had the following characteristics:

She had her own body - beautiful, luscious, strong. Not just that, but Lilith took on her own body. She used all the magic she had here in hell before she was sent topside. " Created her own portal to take Katie back to Earth. "She walked over and took that Angel girl back to Earth through her own portal. She used all her energy here in hell, and as far as I understood, the power she had here doesn’t necessarily transfer to Earth. If it had, we would’ve seen a lot more frozen demons over the last couple of years. I don’t even remember her having that power in hell when she was here.

So Lilith, even though she had the opportunity, chose to return to Earth with Katie, and co-exist with her.