Dawn Matter. Crossroads of Crosstime, #2

Murphy had been lucky. He managed to retire from a business that literally eats souls and had kept secrets into old age that frequently get people killed. All it had taken was a literal deal with the devil. But once you've made yourself unusual at a particular level, certain people and not-quite people tend to remember your name. And being old, useless, and used up is no guarantee that the non-quite people who actually run the world won't show up one day with an offer you can't refuse.