Le Bateau d'Acajou (Un thriller de Sam Reilly t. 2)

The blend of history and myth creates a unique atmosphere. I'm curious whether this was a deliberate choice or evolved during writing.

I loved the world-building, but some sections felt slow. Was that intentional to build atmosphere or a necessary part of the plot?

Their backstories added depth, but I wonder how much of that was planned from the start versus developed as the story progressed.