The FX public-relations team described “The Strain” season finale as a “game-changer,” which is something of an overstatement. But the finish did see this nifty and entertaining vampires-among-us drama sacrifice a few key players while reshuffling alliances, capping off a first-rate sophomore season and creating plenty of possibilities for the third. Granted, there are a lot of creepy-crawlies running around TV these days, but few with a higher pass-the-popcorn factor than this.

Although the buzz related to the finale (and SPOILER ALERT) if you haven’t watched) will surely be about the death of Nora (Mia Maestro), infected by her lover’s vampire-turned ex-wife, the most memorable sequence came early. In what has become the show’s spine, aged vampire hunter Abraham Setrakian (David Bradley) engaged in an auction for a mystical book, the Lumen, vying with longtime nemesis Eichorst (Richard Sammel), as the two snarled insults at each other — the concentration camp survivor dismissing the former Nazi as The Master’s lapdog, while the vampire fiendishly reminisced about all the losses Setrakian had suffered.

That relationship, and the ability to delve back into it, has enriched the show immeasurably beyond the cat-and-mouse game between the factions. The season’s highlight, in fact, was the episode that explored Eichorst’s history, and how he was a struggling salesman — in love with a Jewish girl, no less — before being seduced by the siren song of the Third Reich. If an actor’s going to make a career out of playing Nazis, you might as well be really, really good at it.

Granted, “The Strain” has faced a formidable challenge inherent in any series like this one, bringing its central combatants into conflict without moving the battle toward anything approaching resolution. That was why Nora’s death — and to a lesser degree, The Master’s show of strength by killing the girlfriend of Eldritch Palmer (Jonathan Hyde) — felt necessary, reminding the audience of how serious the stakes are, as well as the Faustian bargain the mogul has made in dealing with the Strigoi. That said, it was certainly a rough episode for female characters, and further evidence that sleeping with Eph (Corey Stoll) is hazardous to one’s health.

Written by showrunner Carlton Cuse and Chuck Hogan (who co-wrote the original novels with Guillermo del Toro), the finale closed by forging an uneasy partnership between Setrakian and the vampire hybrid Quinlan (Rupert Penry-Jones, a splendid addition), realizing the Lumen might hold the key to drawing out The Master and thus granting them the vengeance that both seek. Shrewdly, the show has gradually advanced deeper into this mythology and the notion of warring Strigoi, in a much more gradual and thoughtful manner than, say, “Falling Skies” did.

As noted in the past, even with all the death and throat-sucking, “The Strain” feels like a tonic for some of the choking darkness that characterizes most FX dramas, a throwback to old-fashioned escapism executed at an extremely high level. That sustained quality, notably, hasn’t benefited the ratings much, with the series down about a third in terms of viewers from year to year in same-day viewing.

Nevertheless, for the very busy Cuse, “The Strain” represents his most satisfying series since “Lost.” And despite some initial skepticism that there was anything new to be done with the vampire genre, this TV version of a page-turner has managed to get under one’s skin.