LOS ANGELES — The “Game of Thrones” finale Sunday means viewers will get their last taste of the blood and the Westerosi fight that has been spilling it.

But back in Hollywood, the battle is still very much underway. Even after House Lannister, Targaryen or Stark end up controlling the Iron Throne (or collapsing in a fatal heap), premium television networks will continue waging war, seeking a new show to rule the world “Thrones” created.

Netflix, Apple, Amazon and Showtime have all been feverishly working to reconstruct the scale, acclaim, relevance and — not to be underestimated — subscriber-attracting properties of the HBO smash.

“There is an arms race going on for event television,” said a veteran TV executive who has spent years at a premium platform, using the term for the expensive and location-heavy show with big-canvas plotlines. "There could be multiple winners. Or there could be no winners at all.”

Netflix has “The Witcher,” based on a supernatural-monster literary franchise; Showtime has “Halo,” adapted from one of the most popular video-game series of all time. Amazon seeks to bring viewers back to the Shire with “Lord of the Rings”; Apple is hoping to finally give life to Isaac Asimov’s sweeping “Foundation.” And HBO is going back to the well, developing a “Game of Thrones” prequel starring Naomi Watts.

The scramble isn’t happening just because the end of “Thrones” will leave a massive audience looking for its next epic (or, lately, a target for social-media outrage). For networks it’s about taking advantage of a new set of rules. Swords-and-scepters was once overlooked material — the stuff of a Tolkien adaptation in the movie theater every few years and, at best, a niche show on weekly television.

Yet “Thrones'” has turned in to the dragon that lays the golden eggs — it has averaged some 18 million viewers per episode this season, more than 50 percent above even the much-watched “The Sopranos” finale. HBO Now subscribers spiked by 91 percent during the seventh season.

That success has changed how executives think, increasing the acceptable risks and price tags for a new genre series. (Budgets for a “Thrones” episode can now come in at more than $10 million, several times that of most high-end series.) Their logic is that not only is it worth making shows in categories like fantasy and science fiction — it’s worth spending a lot on them, too.

Given how elusive a hit can be amid the present TV crowds, that means a lot of executives could soon be taking a bath.

Consumers? They could be swimming in event-TV content.

This week we take a look at a Season 2 vision that foreshadowed Daenerys's descent into madness. (REF:hashemis, REF:taylord/The Washington Post)

The battle unfolds

David Nevins was looking a little nervous.

The executive at CBS and Showtime, HBO’s longtime pay-TV rival, had just finished talking about its prized video-game adaptation “Halo” to reporters in a Beverly Hills hotel last summer. He didn’t offer many details on the science-fiction show, about an interstellar war between humans and the alien supergroup The Covenant. But journalists knew the stakes.

“Will this be your ‘Game of Thrones?’ a reporter asked Nevins.

“This will be our ‘Halo,’” he said, then made a distinction. “It’s a different genre — futuristic, space-based science fiction, not fantasy.” A few people in the room bought it, anyway.

“Halo” is an apt spiritual heir to “Thrones. It has the power struggle, the spectacle and the double-crossing. Though springboarded from a video game, it contains juicy central characters and names of “Thrones”-ian dimensions (Master Chief John-117, The Arbiter).

But that also makes it a good candidate for failure — with a sprawling mythology across an original trilogy, a second trilogy, spin offs, novels and graphic novels, the source material may be too unwieldy for eight hourly episodes.

That’s partly why “Halo” development has been going on for nearly six years. Top-tier filmmakers such as Neill Blomkamp of “District 9” and Guillermo Del Toro each took a look and eventually went away. After bringing on acclaimed TV writer Kyle Killen as showrunner, the network last month hired a second showrunner, Steven Kane of TNT’s “The Last Ship.” But it’s still seeking key cast members and a production start date.

Gary Levine, Showtime’s entertainment co-president, talks about it with longing. He says the key may be finding people not known for sci-fi, the way “Thrones” found its voice with a pair of creators not known for fantasy.

“Our hopes and dreams is this will have enormous appeal to ‘Halo’ fans and also appeal to drama fans,” Levine said.

Making Psychohistory

In a sign of these event-TV times, the “Foundation” trilogy once attempted as a movie is now getting new life as a TV show. And from Apple, the emerging streamer with hopes for HBO-like dominance.

Previously, the source material was by turns attempted as a film at Fox, Warner Bros. and Sony, the license passed from around like a dog-eared copy of “The Fountainhead” at a college dorm. It’s easy to see why: The literary work is a classic, not just a genre exercise but a deep contemplation of global power politics via something called psychohistory. Empires rise and fall in “Foundation” in ways that make Westeros look like a city council election.

And yet that same sprawling quality is why the material has not been produced. Apple may face a similar challenge to the film studios, and to Showtime: the problem of too much myth. (Neither Apple nor Showtime would comment on their bets.)

That’s why despite a green light, writers and a producer-financier, “Foundation” lacks a cast and start date. The show was, tellingly, barely mentioned at the service’s high-profile presentation in March.

“There are a few reasons this kind of programming has stayed mostly in film,” said a veteran television producer who has tried to get a number of big-event programs off the ground. “Consumers have usually wanted to see this stuff in movie theaters. And the creative elements can be hard to fit even into a multi-episode series.”

Rolling the Dough

In some ways, the fight to follow “Game of Thrones” is a lot like the game of thrones itself: You win or you die. There is no middle ground.

Spending that much on a series sets a bar for profit and viewership very high, and shows that don’t reach it can fail badly.

But those risks aren’t deterring some players -- and may even be motivating them."

In 2017, Amazon paid a reported $250 million for the license to “Lord of The Rings.” For a license. (Rights to underlying material tends to go for a few million at most.) Production costs, according to some estimates, could take the show to $1 billion.

Amazon is now planning a prequel to the events of the original “Lord of the Rings” novels, hiring writers from “Star Trek" and targeting the series for 2021. (Amazon’s chief executive, Jeffrey P. Bezos, owns The Washington Post.)

“We feel like Frodo, setting out from the Shire, with a great responsibility in our care — it is the beginning of the adventure of a lifetime,” Amazon Studios chief Jennifer Salke, who was hired in 2018, recently told reporters.

Frodo’s adventure also included captivity at the hands of a giant spider and a stalker who eventually bit off the hobbit’s ring finger. Observers see plenty of risk for Amazon as well.

“It could be a massive failure in the making. Or it could be a ‘Game of Thrones’-sized cultural event,” wrote Nerdist. And some in Hollywood have questioned whether a billion-dollar show could ever be justified.

So why is Amazon doing “LOTR”? Because that, experts say, is how big the post-“Thrones” prize really is.

Netflix mounts its horse

Ironically, it is the typically free-spending Netflix, which bid against Amazon for the “LOTR” license, that may end up with the most cost-effective post-“Thrones” option.

Ted Sarandos, Netflix’s chief content officer, tipped his hand on the service’s ambitions to capture the Dinklagian crowd.

The company, he told Wall Street analysts recently, has “a big new original series that we’re currently shooting in Hungary called ‘The Witcher.’ ” It is, he said, “enormous European IP, a very popular game and book that we think is going to make a really fun global series.” (Netflix and Amazon wouldn’t comment on their shows either.)

The global-domination boast is rare for the Netflix executive, who usually speaks of shows of interest to particular foreign markets. But one can understand why he made it: Based on the Polish writer Andrzej Sapkowski’s fantasy series about monster hunters with supernatural abilities, “Witcher” has a uniquely “Thrones” pedigree. It’s literary work with a pulpy setting.

Most important, “Witcher” has something nearly all the other shows don’t: an airdate. Netflix says it will debut it in the fall.

The wedding bleeds red

When “Game of Thrones” was being developed, HBO was skeptical — really skeptical. The original pilot fell so flat with executives they ordered much of it reshot. Creators David Benioff and D.B. Weiss, now seen as infallible kingmakers, were on the verge of becoming one more writing duo in search of a general meeting. The show nearly didn’t end up on the air.

When it did, few expected it to be a mainstream hit, watched not just by teenage Tolkien fans but by their grandparents. That feat is hard to replicate — not only for the obvious reasons, but also because the Hollywood system is designed to find its phenomena elsewhere. The most original shows come, almost by definition, from left field, developed without the weight of network hopes or the baggage of viewer expectations.

“When you take on a big franchise, it usually means a lot more cooks in the kitchen. And the pressure is so high everyone’s afraid to take chances,” said an executive who has overseen several big projects and is not involved with any of this wave.

HBO’s “Thrones” prequel may attract plenty of curiosity. But internally the network has high hopes for another show. “Demimonde,” from J.J. Abrams, centers on “a world’s battle against a monstrous, oppressive force,” which also describes several political documentaries currently being shot. Abrams basically helped created modern event television with “Lost,” so the expectations are plausible.

Amazon may be about to experience a similar dynamic. Its game-changer could well be not an “LOTR” prequel but “The Power,” based on Naomi Alderman’s book about a future in which women develop electrocutive power and use it to topple a patriarchy.

“I don’t know if it will be a huge spectacle kind of show but I think what makes it special is that it’s an amazing story, something new and provocative that can frighten and enchant you, something that’s based on very good writing," Reed Morano, the Emmy-winning director who will direct the series, told The Post. “And isn’t that what people are really looking for?”

Morano won an Emmy for directing Hulu’s “The Handmaid’s Tale,” which may have come closest to finding some of the “Thrones” mojo — a dark show that went popular (and won awards) thanks to its vision and commentary. But as a third season prepares to launch with less heat, it has also reminded how hard is it to duplicate Hollywood momentum.

HBO itself has suffered the folly of chasing past success. Completists, and they alone, will remember HBO looking for a David Milch repeat after “Deadwood” with "John from Cincinnati.”

“The next 'Game of Thrones’ won’t be anything like ‘Game of Thrones,’” said the executive who has worked on event-television projects, which makes all quests to find it urgent and all articles about them, including this one, eventually superfluous.

Even if one of these shows succeeds, that doesn’t mean perpetual riches. For all its “Thrones” spikes, HBO Now has seen subscriber numbers drop as much as 40 percent within three months of the season’s end. Few are capable of ascending to the Iron Throne. And almost none can remain there.