I this supposed to be longer?
It stops abruptly so I wondered if you meant to post more. Apart from that, it could do with a little editing especially at the start. It reads more like setting a scene in a screenplay maybe than actual prose.

But you asked about whether the story-idea appeals to us. For me - I did like the idea - until she turned into a demon herself lol. There you lost me a bit, but that might just be because the story is cut off.
I think what I lacked was the atmosphere of the supernatural - it just launches into it without much preliminary stuff... I would flesh it out a bit. Of course, you haven't really come to the sexy yet - I suppose there will be scenes between Erica and the Monster and Erica and Leala?
I do like the idea - I think it has potential