Not so sure why Marx was into the supernatural and fictional so much, but he did start the Manifesto with the idea of such being in mind.
Helen Macfarlane translated the concept as hobgoblin, usually provided as spectre later on.
I have often thought of the proximity with Hegel's Spirit of the Times. The motivator and gist of the moment in history. The Now. The mass psychological sum of humanity as brought to here by its thought and philosophy-ideology.
Perhaps it is a spirit, but why is it demonic? Why is there a need to present The Spirit of the Times as an evil. Such an attitude represents the generated hate against the powers that be by the little men with lots of power - the hobgoblins. That rather than a fair, just, emancipating force.
The evil represents the blindness of emotional attack laid on, or perhaps formed and kibitzed, even agitated on by the revolutionaries. Soothsaying of the doom by a hand of evil turned out to be evil incarnate itself and not a spectre at all.
The spirit has transformed our society that has been transforming the spirit in eternal endless reflexivity. The chaos has subsided - for a bit. And the spectre? - asleep.
Snores with spirit or sees the demon?