Blackstone Fortress is a tie-in novel. OK, all Warhammer 40,000 novels are tie-in novels by definition, but some are more tie-in novels than others. Whereas many pieces of Warhammer 40,000 fiction take inspiration from the game universe and its various sources of lore, Blackstone Fortress by Darius Hinks is intentionally crafted to coincide with the release of a specific Games Workshop product.
The product in question is Warhammer Quest: Blackstone Fortress. Warhammer Quest, back in the day, was a sort of followup to the classic HeroQuest boardgames which had such memorable TV adverts. HeroQuest itself was Games Workshop’s take on the “dungeon crawl” subcategory of boardgame, which for a long time HeroQuest was the most famed and widely-played example of until it fell out of print, Warhammer Quest superseded it and then also fell out of print, and then new games in the same vein like Descent or Gloomhaven and the like arose to fill the vacuum.