story identification - Book featuring a woman who is kept alive by parasite feeding during copulation

I remember only some facts from the book I will list them below:

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  In the book there were several story lines which then converged together.

  
  



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  One of the figures was a man who was not really a human. He was sentenced to death by drowning. The idea was the convict was thrown into the harbour with a heavy weight and if the convict managed to get to the other side he would be set free. This character managed to do it because he had 4 lungs, as he was not human. The man was stronger and taller than regular humans, but mentally he was like a small child.

  
  


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  Next there was a female, who was basically a zombie. She was cursed, so she could not rest after death. She has purchased a parasite which substituted her nervous system. The parasite had to be kept alive by having frequent sexual encounters. She was a thief and later became ship captain (pirate captain even, I think).

  
  


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  The third character was an old eccentric man who lived on the roof of his house together with several hens. He had a brother. During the plot of the book he managed to run a "company" which earned him a lot of money. Which he then used to free the slaves in the kingdom and move them offshore to their native islands.

  
  

  
  

  It was later revealed that the man was in his younger years responsible for the inflation scheme which lead to the economical collapse of the kingdom, leaving him very rich.

  
  
  

  
  


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  All three of them then work together to free the slaves.