What's he doing here?

Everything was going well for you. You had great friends, a great home, and a great place to live.

That was before a specific Dream Demon showed up at your doorstep.

Couldn't be too bad, right? I mean, it's only a demon that can start the apocalypse and manipulate almost everything to its will. What could go wrong?

(Please note, this is an AU where Reader-Chan is gender neutral and Bill is human-ish. And they're around the same age, aka around twenty.)