LOS ANGELES  — A preeminent spiritual organization that keeps a Sunday Sabbath reached one of its high holy days this past weekend as Downton Abbey celebrated its season finale.

“For behold! My Lord Grantham is master of his manor once more,” declared Downton fan club president and self-appointed high priestess Kristy Cline-Humphries. “Losses beset our most holy Abbey and tragedy rained down about our heads, but with an heir to hold the line and finances secure, our good Lord is once again king of all he surveys.”

Cline-Humphries added: “Amen.”

Downton Abbey averages more than 6.5 million viewers a week, meaning it has twice as many American believers as Episcopalianism and Islam combined. It is dwarfed, however, by the Sunday cable religion with the most violent and extreme fanatics (or “fans”): The Unholy Church of The Walking Dead, whose followers outnumber American Buddhists, Jews or Presbyterians.

Sociologists say once Sunday was set aside for ancient Christian rites, such as the singing of hymns, the burning of incense and transubstantiation. Now, however, in groups both large and small, the faithful gather with food and drink in shadowy, communal rooms with glowing electronic oracles to hear the words of dark prophets whose names include Walter White, Nicholas Brody and, in some very few holdout instances, Dexter.

Friday and Saturday evenings, experts say, are still perfectly acceptable for other spiritual services, as there is nothing good on.

“Game of Thrones might not seem to have much in common with other major religions,” said anthropology expert and Stanford researcher Brett Wharton. “Its dues are paid on time, its followers are loyal and it’s socially acceptable to argue about it in public. But if you look closely, all the hallmarks of a theological institution are there: miracles and disasters, conflicts that pass from generation to generation, and, of course, a hierarchy among followers based on who encountered their sacred texts earliest.”

“Also breasts,” Wharton said. “Lots of breasts.”

As the practitioners who call themselves “Rick’s Gang” go to “war” with “Woodbury,” Wharton believes tensions over who does what on Sunday from 8 p.m. to 11 p.m. EDT will only increase. Sunday worshippers may turn to Girls for social mores, he says, but they turn to The Unholy Church for blood, battle and gore.

“Holy shit, did you see this past Sunday?” Wharton asked. “That was so awesome I nearly lost it. Truly profound and spiritually fulfilling. I can’t believe some people were watching moldy old PBS. Still, I wouldn’t worry too much about a religious war in America anytime soon. At least not until Mad Men returns in April.”