I'm looking for a term (preferably a short one and definitely a single word, if possible) that describes someone (or something) that brings bad news. I.e. someone whose sole (or at least main) purpose is to give others sad notifications, failure information, error messages etc.
No need to be colloquial. In fact, the more formal the better.
For instance, one who brings condolences would be condolencer or possibly regret expressor (yes, I'm perfectly aware those aren't proper words - I made them up right now with the purpose of conveying the intention of my question).