(CNN)The following contains spoilers about "The Walking Dead's" fourth episode.
"The Walking Dead" is following what has become a familiar pattern for the AMC hit, as it reaches the midway point of the opening eight-episode flight of a grim, grueling, inordinately sadistic seventh season.
The drill goes something like this: Open with a bang (and then some). Move away from that to pursue lower-key, stand-alone episodes involving different characters. Return to the central plot, before finishing -- last season, anyway -- with some sort of giant cliffhanger, however irritating and manipulative that might be.
The X factor thus far, as Sunday's expanded 85-minute episode made clear, is Jeffrey Dean Morgan's Negan, a charismatic sadist who carries not just a baseball bat but the constant threat of murdering someone at a moment's notice.
Having appeared in three of the four episodes, Morgan has very quickly grabbed the series by the throat and become its centerpiece. Yet the sense of undeniable menace he has brought to the show has been accompanied by uncomfortable, provocative and in some ways problematic themes, beginning with his overt intent to emasculate Rick (Andrew Lincoln), the leader of the group now under Negan's control.
"I'm not in charge anymore. Negan is," Rick admitted to his community, which didn't stop Negan from again seeking to humiliate him. (Negan's arrival in silhouette literally felt like barbarians at the gate.)
"The Walking Dead" has long focused more on the cruelty that humans can inflict upon each other in a lawless society than any horrors the zombie hordes commit. But Negan's arrival has turned the series into a prolonged examination of life under dictatorial rule, leaving Rick and his gang to contemplate a roster of terrible options that including fighting, fleeing or simply knuckling under to it.
Having witnessed Negan's ruthlessness up close and personal, Rick proposed that third path. "We give 'em what they want, we live in peace," he said. But clearly, others are less sanguine about that prospect, including Michonne (Danai Gurira), which threatens to create some awkward moments around the house.
There's no question Negan's arrival has given the show an infusion of energy, something any series -- even one this popular -- can use this late in its run. Morgan's magnetic performance, however, has come at a cost in terms of the show's "ick" factor, feeling less like an escape than an ordeal.
"The Walking Dead" has never been for the squeamish -- gore is an inherent part of this world -- but at times now risks wallowing in brutality. In the process, the producers have taken a series that its most ardent fans approached with a weekly sense of anticipation and replaced that sentiment, at least for some, with something closer to dread.