Disclamer: Not mi- . . . huh. I guess this one IS mine! Well, the story is, anyway.
Like something from a story, you are saved in the nick of time from a creature of darkness; some un-named horror that had stolen you in the dead of night. Your knight-in-tattered-clothing took you away from that pit and brought you back into the light. It isn't easy, but you slowly return to Life Before: business as usual.
Months later a news story all but kicks you in the teeth. You know it's not the same one that took you, but it's the same kind of Thing.
There is no answer from the number your knight-in-tattered-clothing left behind. The part of you that isn't quivering in a terrified heap remembers all the things that were said After, remembers how to kill it.
So, you go. Because it's the right thing to do. Because you can help. Because everyone needs a knight, even one in tattered clothing. Because there is no one else.
The first time you save someone, first cheat death, you reclaim that part of you that never stopped screaming.
The next time you spot one of those stories, there is no hesitation. You go out and stop the Thing.
It isn't till a year later, at your cousin's wedding, when someone asks what you do that you realized you've changed. The word Accountant no longer fits you, it's too small. There is a darkness in you now. A new word bubbles up to cover the places Accountant doesn't reach, wrapping around this new thing that you have become.
Hunter.