errand-ghost

noun2

1. •
   (rare) A spirit or spiritual messenger; an angel.

   • If that was really insulting, please don't be offended. I certainly don't think of you as my errand-ghost. Actually, I think of you as my friend. — 2008
2. •
   (rare) Any spirit or ghostly messenger.

   • Death is not unknown to him, but she has perished / And her errand ghost wanders through the night. — 2011