I'm looking for manga where the main character used to do something but doesn't anymore even though they were good at it. However, even though they've "quit", whatever they've been involved with comes back to haunt them or influence them later on.
I wonder if Rurouni Kenshin, Black CatHunter x Hunter or Trigun count. One of the main characters in all of these manga used to be fighters/assassins/mercs but then decided to live a more peaceful life. Their past comes back to haunt them in one way or another.