At last, they are laying down the rules; now I'm starting to understand the story a little better.
EDIT: Judging and inferring from the expositions in the chapter, I came up with some personal theorycrafts (until proven otherwise):
- The people/ladies operating in that shady corporate building could be the pantheon from that otherworld;
- The otherworld people pray to those gods, likely the ones that "pray for strength/survival before a major conflict", becoming unwitting "clients"
- The gods grant their prayers through this weird "Earth mercenary system" to augment the client's power
- The gods then channel these mercenaries to the client (in this case, Mr. Kang to Parsons), "fusing" the souls in a way or system that the mercenary is primarily in control, while the client still thinks he is still himself.
- So what's in it for the gods? Probably if the client survives, his faith to the gods would increase, and faith is likely the currency/lifeforce for these gods. Dead client, no faith for the gods, no reward for the merc.
- All that's left is to create some arbritary rules on the mercenary's side like his wages.