Train man

I NEED TO KNOW WHAT HE DOES!! why does he harvest/hunt down spirits from train commuters. I just know he's gonna be important to plot. It's in the way that it's a routine thing for him to just appear and do the same thing every time. Plus the fact that a spirit can jump out and fight back, no matter how feeble of an attempt it may be. There's just no way it's not relevant at all. I want her to come with the old shaman and Rom to the train, just so we can see what they see.