‘The Strain’s’ Richard Sammel found the key to his role in co-creator Guillermo del Toro’s advice

It takes a certain mindset to want to bring about the end of the world. For Richard Sammel, the German actor who plays emissary of evil Thomas Eichhorst in FX’s apocalyptic series “The Strain,” a relentlessly positive attitude and a misplaced sense of self-assurance are key.

“Guillermo gave me a magic word,” Sammel said recently, referring to “Strain” co-creator Guillermo del Toro. “He said, ‘Richard, for every strong character, there is a cue word, and for Eichhorst, it’s, ‘Yes!’ I couldn’t do anything with it for quite a bit, but … at a certain point it just opened. Yes! He’s hubristic, egocentric, narcissistic. It’s the vampire version of Obama’s ‘Yes, we can!’ Yes, I can. Yes, I do the right thing.”

Sammel’s wicked charisma and gleeful zeal have helped transform a character that easily could have tipped into sinister parody (SS officer turned power-obsessed vampire) into one of the most surprising figures among the show’s oddball assortment of unusual heroes and villains.

For the 53-year-old European with the piercing blue eyes, the role is one he approached with relish.

“You always want to play a western, a sci-fi and a vampire movie,” Sammel said. “He’s a little bit the Darth Vader of the story.”

Created by Del Toro and Carlton Cuse and adapted from a trilogy of horror novels Del Toro wrote with Chuck Hogan, “The Strain” sees Eichhorst conspire with terminally ill billionaire Eldritch Palmer (Jonathan Hyde) to transport an old-world vampire known as the Master (Robin Atkin Downes) to Manhattan.

Before long, New Yorkers are turning into violent, insectoid monsters with red eyes, rodent teeth and giant stingers, and Centers for Disease Control and Prevention epidemiologist Eph Goodweather (Corey Stoll) reluctantly joins forces with experienced vampire hunter Abraham Setrakian (David Bradley) to slay the Master’s victims and to eliminate the Master himself. It’s Eichhorst’s responsibility to ensure they fail.

Thanks in part to its B-movie elan and popcorn-entertainment approach, “The Strain” has become a welcome hit for FX, with each episode attracting an average of 4.4 million total viewers. It was renewed for a second season last month.

A veteran performer who has worked extensively onstage and on screen in Europe, Sammel is perhaps best known to American audiences for turns in Hollywood films including “Casino Royale,” “Inglourious Basterds” and the Kevin Costner spy thriller “Three Days to Kill.”

The actor, who divides his time between Paris and Berlin, currently has a starring role in “Un Village Francais,” an acclaimed French drama set during the Occupation. “You will see me with blond hair, a charming, intriguing guy,” Sammel said, “a little bit more human than in ‘The Strain.’ ”

Where the two TV roles converge is the bloody landscape of World War II. In “The Strain,” Eichhorst encounters Setrakian as a prisoner in the camps, and develops a perverse fondness for the young woodcarver, whom he enlists to create an elaborate cabinet as a gift for the Master.

“If you play a bad guy with the conscience of being bad, it’s not so interesting,” Sammel said. “You have to find out what drives this guy, what is his motor. It’s a story of friendship for him, unconscious of the fact that he treats (Setrakian) like a pet, of course. It really gave me a very strong basis to connect with a vampire.”