FX closed out the Hall H programming at Comic-Con International in San Diego with a panel devoted to its vampire drama "The Strain," which premiered its second season that night.

Showrunner Carlton Cuse was joined for a discussion of the new season by co-creators and executive producers Guillermo del Toro and Chuck Hogan, and stars Corey Stoll (Dr. Ephraim Goodweather), David Bradley (Abraham Setrakian), Mia Maestro (Dr. Nora Martinez), Natalie Brown (Kelly Goodweather), Jonathan Hyde (Eldrich Palmer), Kevin Durand (Vasiliy Fet), Ruta Gedmintas (Dutch Velders), Miguel Gomez (Gus Elizalde) and Richard Sammel (Thomas Eichorst).

The first big reveal was that while Season 1 followed the story from the first "Strain" novel fairly closely, about 80 percent of Season 2 will cover new ground. Hogan, who co-authored the horror trilogy with del Toro, welcomed the changes, saying part of the fun is "going back into that world and not having to be beholden to things we've already done. The fun is going back and taking the characters and putting them in new situations."

Del Toro said he and Cuse agreed to take great elements from the books but expand on them, and mapped out a series of marks they had to hit along the way. "Carlton explained to me at the beginning -- and at first I didn't get it -- that a TV show is a living entity," he said. "As it goes from season to season, it evolves and tells you what it needs. At first I didn't understand, but now I know it's absolutely true."

Del Toro & Cuse Talk "The Strain" Season 2, Going Off-Book and Gloomy Vampires

One thing they changed early on was a prologue written to flesh out some of the Master's backstory. It was originally supposed to kick off Season 1, but they decided to instead use it in the Season 2 premiere. Del Toro directed the prologue, which was shown to the audience.

Set in 1932 Romania, the prologue features a young Abraham Setrakian hearing a fable from his grandmother about a man named Jusef Sardu, who was afflicted with gigantism. He was taken on a hunt with his brother in hopes of obtaining wolf's blood to cure the disease. A mysterious creature stalked the group and killed all but Jusef, who followed the monster to a cave in hopes of killing it. Instead, the creature attacked and vomited thousands of worms into Jusef, turning him into the Master.

"When I was a kid, my nana used to tell me the nastiest fucking bedtime stories," del Toro said, "so no matter what you think of the grandmother in this video -- I got worse than that. I thought it should look beautiful and be disgusting." He added that the season will incorporate more flashbacks, some dating back even further than what was seen in the prologue.



Del Toro will also direct a black-and-white sequence featuring Mexican wrestling in this season's fourth episode, thus introducing the history of Angel Guzman -- or Silver Angel (Joaquin Cosio). "It was my favorite day on the set so far," the filmmaker said.

The cast members also spoke about their characters. Asked whether Ephraim will still be drinking heavily, as he was at the end of Season 1, Stoll said he made an effort to differentiate his "Strain" character from the alcoholic he played on "House of Cards." "Eph is much more functional and wise-cracking under the influence,," he said, "which gives me the opportunity to crack some jokes in the middle of this vampire apocalypse."

Hyde said Eldritch will show a softer side in Season 2, hinting there may even be a little romance for him.

Gomez said Gus, who was isolated from most of the cast last season, will have more crossover in his role as vampire hunter.

Fans were also treated to two "comedic" scripted videos. Cuse has a history of putting together special videos for Comic-Con to entertain fans of his shows ("Lost" and "Bates Motel," for example). The first "Strain" video was a behind-the-scenes look at the crew -- except the crew parts were acted out by members of the cast, with del Toro playing a foul-mouthed standards and practices representative and David Bradley playing a burned-out production assistant. The second video was a mockumentary following the undead Nazi lieutenant Eichorst as he solved his unemployment dilemma by renting out his blood dungeon as a bed and breakfast.

"The Strain" airs Sundays at 10 p.m. ET/PT on FX.