It is a pretty well-known fact that dreams are often manipulated by your thoughts just before you go to sleep. If you were playing D2 for a few hours, then went to bed directly afterwards, a relatively soon afterwards, you would most likely have a dream that was somewhat incorporated with a D2 theme.

It's not abnormal.

Surprisingly, no. The closest thing I've dreamt about to D2 is being told by my Father (in a dream) that would I be a Greater Demon someday.

That made me happy. I want wings.