The demons!
They were hear with clear intent - to raise a new darkness demon divinity, but also to protect Eva from the shadows. She has come here on her own with a clear revenge, but she was also valuable lady to the demon's world.
Her weapons could allow them to hold their souls and even protect them deeper!
It was only available for the hell's pillars as the lady had her own goals to achieve. Even so, they couldn't just allow her to risk her life like that! She was using them and so they were also using her powers for themselves.
it was a good cooperation, but one of the sides was not really caring about it at all.
Even more, after she has learnt something 'valuable'...
However, the lady wasn't really willing to give up on her revenge and wait! This something 'valuable' was naturally Xue Ren's reincarnation, but Eva herself was wounded way too deep to stop now.