The humans may have lost a pivotal battle at the end of season 3, but for the remaining resistors on The Strain, the war rages on in the series’ fourth and final season, which premiered on July 16th on FX. To look ahead at the show’s swan song, we recently joined other reporters on an interview call with showrunner Carlton Cuse to talk about wrapping up the apocalyptic storylines, co-creator Guillermo del Toro’s involvement in the fourth season, and much more.

During the interview call, Cuse talked about the extent of del Toro's involvement on the fourth and final season:

"It’s been a wonderful collaboration and division of duties, and as always, Guillermo remains in charge of the creatures and visual effects and the color timing and really the look of the show, particularly in this season, when our characters are living in nuclear winter—that was all guided by Guillermo. He was directing this movie The Shape of Water and therefore was not available to do any directing this season, but he has remained very much involved in the visual creation of the show and also has lent his talents and provided narrative input, particularly as it relates to the ending of the show, that’s something that Chuck, Guillermo, and I discussed in a lot of detail."

Cuse went on to talk about the "mentor/mentee" relationship between Zach and The Master:

"We presume at the end of season 3 that Zach and The Master have gone off together. It’s kind of a mentor/mentee relationship. Zach is hopefully one of the evilest child characters in the history of television and who better to mentor him than a giant, parasitic, vampiric creature."

Cuse also reflected on how soon the ending of the series was conceived and how the creative team worked towards that conclusion:

"It evolves across time. You make a television show and the more time you spend in that creative world, the more you learn about the world, the more you think about the world, the more the characters evolve. Pieces of the ending arose across time. During season 3, Chuck [Hogan], Guillermo, and myself, we all looked at the amount of narrative that we felt we had left, and we felt that one more ten-episode season was the right amount of time to end the show. When we sat down to plot out season 4, the thing we really focused on at the beginning was really what our ending was going to be. We already had certain ideas about what characters would be doing and where they would be going, but it was really at the very beginning of season 4 in the writing process that we figured out what our ending was going to be, and then we wrote towards that. That was very exciting. It’s wonderful to be in a position to determine the ultimate fate of your characters."

Cuse also discussed what the core characters are trying to achieve in the fourth season:

"The ultimate overall goal is to try and defeat The Master. Our characters may be down and they may be living in nuclear winter and they may no longer be at the top of the food chain, but they are still determined to defeat the forces of evil. That’s fundamentally what this story is about. At the beginning of the season, we’re starting out more in survival mode, but Fet is running around in the Midwest trying to get a nuke, and he’s trying to get a nuke because he believes the nuke is the thing that’s going to be able to bring The Master down. Our characters may be very disadvantaged at the start of the season, but they still have this larger goal of ultimately conquering this global parasitic force."

Cuse also mentioned that even if you've read The Strain books by Hogan and del Toro, that doesn't mean you'll know exactly how the series ends:

"If you’ve read the books, the show is its own animal, and it has its own narrative journey, so I don’t think you can watch the final season of this show and think you know what’s going to happen to any of the characters. All bets are off. If you’ve read the books, don’t think you know what the fates of the characters are. The ultimate thing about the last season of this show is that you get to find out the ultimate fate of each of these characters is, and that’s very exciting, and in the case of our show, in a lot of ways, very surprising."

Cuse confirmed that flashbacks (reminiscent of his work on Lost) will continue to play a key role in the series, right up to its conclusion:

"Absolutely. There is even a flashback in the final episode. It’s always been a good way for us to really provide some resonance about these characters, and that’s something that we’ve done since the beginning, and we’re going to continue to do it in this last season."