What's a word for a person who deals or takes care of other people's problems?

I need a precise word or title that describes a person who takes care of other people's problems.A person who covers up someone's tracks or cleans up someone's mess.

Imagine, a person who has too many connections, has an authority and everybody respects him, but always stays in the shadows and only reveals himself when someone asks him to do their dirty work.


fixer comes to mind

A person who makes arrangements for other people, especially of an illicit or devious kind. ODO

Consider the Showtime series Ray Donovan. See the Premise.