The Story of Pyke
Pyke was a harpoonist on a whaling ship called the Terror — a man whose job required both extreme skill and a tolerance for the specific danger of deep-sea hunting. When a monster they were pursuing grabbed him and dragged him into the deep, the captain cut the line rather than lose the ship. This is a pattern in Bilgewater. The deep takes people, and the people above calculate whether the loss is acceptable, and sometimes the answer is yes.
He did not stay dead. Something in the deep gave him back — or kept him and changed him into something that could continue. He returned to Bilgewater with a list of names and the specific skills of a hunter: able to become a shadow, able to move through crowds unseen, carrying a harpoon that he uses with the precision of someone who has spent years aiming at things in motion. He is killing the crew of the Terror, one name at a time.
He is not limited to his personal list. He has expanded his criteria: everyone who has committed acts of Bilgewater-style abandonment, who has left people to the deep because the calculus came out unfavorably, is potentially on his list. He operates as a kind of oceanic justice that the city's formal institutions don't provide. Whether he is right about who deserves it is a question complicated by the fact that the thing that brought him back may have altered his judgment as much as his body.