Five years ago, auteur director Guillermo del Toro (Cronos, Hellboy, Pan's Labyrinth) set out to create a bold, new vampire series for television — and had every door slammed in his face. But the writer/director was convinced his take on the classic monster would speak to an audience that had grown weary of sparkly fangs and doomed romances. So, along with novelist Chuck Hogan (Prince of Thieves, which became the Ben Affleck-led The Town), del Toro committed his tale to paper and, in June 2009, The Strain hit bookshelves.

However, copies didn't stay there very long, as del Toro's hunch proved correct and his story of an uncontrollable vampiric virus and the five people determined to stop its spread, caught fire, racing up the New York Times' best-seller chart. That's when, in the ultimate irony, dozens of networks attempted to buy the TV rights.

"As soon as the first novel hit the top 10 on the New York Times list, we got calls about the rights," del Toro told BuzzFeed at The ATX Television Festival, with a laugh. "But I wouldn't sell the rights until the trilogy was published because I didn't want to be thinking about the movie or TV show during the writing process." After two equally popular sequels — 2010's The Fall and 2011's The Night Eternal — del Toro quickly partnered with cable channel FX and executive producer Carlton Cuse (Lost) to bring the gory saga to screen.

And while del Toro makes it very clear that he defers to Cuse when it comes to running the show, his fingerprints are all over every episode. "I supervise every single shot in the show," said del Toro, who co-wrote and directed the pilot episode, which airs July 13. "Every piece of FX you see in the first season is guided by me, I do the final color correction on every episode, I go to Saturday unit when they're shooting the monsters when I can and assist the guys shooting. I discuss my suggestions with Carlton; now and then I fiddle with the scripts, but I know in my heart of hearts that Carlton is king and I follow his lead — but I do want to be part of the whole thing."