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Age Is More Than Just a Number
The first and most vital change showrunners D.B. Weiss and David Benioff made to George R.R. Martin's Song of Ice and Fire saga? The books take place 14 years after Ned and Robert's rebellion against the Targaryen dynasty; the show, however, takes place 17 years later. This in turn allowed Benioff and Weiss to age each of the story's young characters by two or three years—a shift that makes all of their engagements, literal or otherwise, a little easier to swallow. (In the show, Daenerys is 16 rather than 13 when she's married off to Khal Drogo, for example.) Even Martin has admitted that aging up Dany, the Starks, and the Baratheons leads to more story possibilities; he's said himself that he initially intended his child characters to grow more during the book series, only to discover that his plot moved too quickly to allow for the type of growth he wanted.
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The Happy Hooker
A Song of Ice and Fire can be punishingly dense—let your attention wander for even a moment, and you'll be forced to take trip after trip to each book's appendix in a vain attempt to remember who, exactly, all these weirdly named people are. Why, then, would Game of Thrones ever bother adding another character to the mix? Simple: Giving screen time to Esme Bianco's Ros, a prostitute by trade, meant numerous opportunities for Thrones's patented "sexposition"—i.e., expository dialogue made less boring by a healthy infusion of boobs. She also represented the scores of common folk whose lives are affected by Thrones's highborn characters, sometimes fatally—as Ros's own is, eventually, when she finds herself at the wrong end of Joffrey's crossbow.
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Young, naïve Robb Stark finds himself in a tough spot in the second Song of Ice and Fire book: Though his mother has betrothed him to a daughter of Lord Walder Frey, he's so overcome with grief when he learns (erroneously) that his brothers Bran and Rickon have died that he seeks solace in a young nurse named Jeyne Westerling. In order to preserve Jeyne's honor after their tryst, she and Robb marry the next day. It's a coupling that comes out of nowhere for Catelyn Stark—and book readers. Thrones remedies this by erasing Jeyne from the narrative, replacing her with an entirely new character: Talisa Maegyr, a feisty noblewoman from Volantis whose romance with Robb is more of a slow burn—meaning that their secret marriage doesn't come as as much of a shock.
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We'll Drink to That
Arya finds herself in a tough spot in the series' second novel, trapped at a supposedly haunted estate called Harrenhal and roped into being cupbearer for visiting lord Roose Bolton. The show switched things up by swapping Roose for another, more established character: Tywin Lannister, fearsome father of Cersei, Jaime, and Tyrion, as well as the true power behind King Joffrey's throne. Pairing him with Arya was a savvy move that gave more screen time to Tywin portrayer Charles Dance—and allowed Dance to share scenes with Maisie Williams, which never would have happened had Benioff and Weiss followed Martin's book storyline.
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Fail the Conquering Hero
Theon Greyjoy briefly becomes Lord of Winterfell in both the books and the TV series, but there are numerous small deviations between how each one plays out. Chief among them: In the books, Theon is aided and abetted by a stinky prisoner named Reek, who turns out to be sadistic Ramsay Snow in disguise—and who eventually incapacitates Theon, sacking Winterfell and taking the Ironborn prince prisoner. Theon and Ramsay don't appear again until A Dance with Dragons, three books later. The series opts to cut out this bit of business, keeping Ramsay off screen entirely until after Theon loses Winterfell.
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Book Daenerys has a series of cryptic visions when she enters the Qartheen warlocks' House of the Undying, bits and pieces of backstory and prophecy (a blue flower growing from a wall of ice! "Three fires must you light!") that book readers are still trying to parse. TV Daenerys, however, finds fewer riddles when she enters the House, instead seeing a few of the series' many settings (the Red Keep, Castle Black) before being tempted by a vision of her beloved Drogo and their stillborn son.
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Tyrion suffers grievous injuries during the Battle of the Blackwater in book 2, leaving him horrifically wounded and mostly noseless. The show elects instead to leave him with a relatively dinky scar—largely because, as Peter Dinklage told EW in 2013, staying true to the books "would cost a lot of money because they'd have to put a little green sock on my nose… They'd have to [digitally paint] over my face in every frame, and that's costly and time consuming. I think a scar solves everything."
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An Even Redder Wedding
Robb's book bride, Jeyne, isn't even present at the infamous Red Wedding when it occurs in A Storm of Swords; Catelyn and Robb are worried that Lord Frey would be offended by her presence, since marrying her meant Robb breaking his promise to marry a Frey daughter. Maybe they were right to worry: Talisa, Jeyne's stand-in, is present at the Wedding on Thrones… and because of that, she's murdered in the most horrifying way possible via a dagger to the belly. Oh—did we mention that while Jeyne isn't pregnant, Talisa is? You'd think there wouldn't be a way to make this sequence any more horrifying than it is in A Storm of Swords—but somehow, Thrones manages.
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Playing For Keeps
How do you solve a problem like Bran Stark—whose post-book 2 storyline is, essentially, a whole lot of walking in the snow? The TV series attempted to inject some life into it by having Bran and co. stumble upon Craster's Keep, where they're summarily captured (and Bran's pal Meera is, of course, almost raped). Though Jon travels to Craster's Keep just once in the books, he ends up going there again in the TV series, leading an almost-reunion between him and Bran—but in the end, the show resists the urge to go that far off book.
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The White Stuff
White Walkers—the ancient race of ice demons slowly growing more powerful North of the Wall—generally have more of a presence on Thrones than they do in A Song of Ice and Fire. Book readers have only technically "seen" one at this point in the saga—the one Samwell Tarly kills with dragonglass in book 3. The TV series, however, has shown us Walkers on several occasions, most notably at the end of season 2—when a terrified Sam sees an army of Walkers and reanimated corpses preparing to invade the world of men—and in season 4, where we see a Walker scoop up a son of the wildling Craster and apparently transform the baby into a Walker himself. Though the books indicate that Craster sacrifices all of his male children to the Walkers, that fact is made explicit onscreen.
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Did Jaime rape Cersei next to the corpse of their dead son? Judging from the way Cersei received her brother's advances on the TV series—trying to resist him and clearly saying "no"—the answer certainly seems to be "yes." In the books, though, the same encounter is very obviously consensual... with the caveat that we're getting the scene from Jaime's perspective, so it's possible an impartial narrator would disagree with that assessment. Martin himself recognized that there were issues with the way the scene played out on TV, telling readers, "The scene was always intended to be disturbing… but I do regret if it has disturbed people for the wrong reasons." (For the record: Actors Lena Headey and Nikolaj Coster-Waldau both say the scene wasn't meant to be a rape.) It's worth noting that this wasn't the first time Thrones transformed a consensual sexual encounter into forced intercourse; see also Dany's first night with Khal Drogo.
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First Wife's Club
In both A Game of Thrones and the first season of Game of Thrones, readers and viewers learn a vital bit of Tyrion backstory: As a teenager, he married a commoner named Tysha, only to be forcibly separated from her by his father, Tywin. Tyrion later learned that Tysha was a prostitute, hired by his brother Jaime to make a man out of Tyrion... and was then forced to watch Tywin's guards rape her one by one. In A Storm of Swords, however, Martin has Jaime confess that he misled Tyrion all those years ago: Tysha wasn't a prostitute, and she really did love Tyrion. Tyrion is understandably infuriated by this, and Jaime's revelation becomes his primary motivation to kill his father. Perhaps because it'd been years since Tysha merited a mention on the show—and because Tyrion already had plenty of reasons to want Tywin dead—Thrones chose to leave out the Tysha twist entirely, allowing Tyrion and Jaime to part on much friendlier terms.
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She's No Lady
A Song of Ice and Fire certainly isn't short on twists, but this one's a real mind-boggler: At the end of book 3, readers learn that Catelyn Stark—murdered at the Red Wedding—has since been resurrected as a vengeful, mostly mute ghoul now known as Lady Stoneheart. Alas, the character has yet to appear on the TV show, and book fans shouldn't hold their breath for her: "Yeah, the character's dead. She's dead," Michelle Fairley, who played Catelyn, told EW last summer. And by "dead," she means dead-dead—not undead.
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A Stark Contrast
A Song of Ice and Fire's later books are sprawling narratives that seem bent on moving Martin's point-of-view characters farther and farther away from one another. The TV series, however, seems invested in seeing these characters converge sooner rather than later. Case in point: In the books, Brienne—on a quest to find and protect the Stark daughters—is unsuccessful before she's waylaid by Lady Stoneheart. On the show, though, Brienne encounters both Arya and Sansa—neither of whom consents to come with the Maid of Tarth.
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The Royal Beast with Two Backs
The books' Tommen Baratheon is a chubby-cheeked eight-year-old who loves nothing more than stamping royal documents and playing with his kittens, Ser Pounce, Lady Whiskers, and Boots. On the TV show, though, he's a teenager—which means that while both Tommens marry Joffrey's widow, Margaery Tyrell, only TV Tommen can consummate their relationship. It's a major change that drastically affects the already frosty dynamic between Margaery and Tommen's mother, Cersei.
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I Thee Dread
By this point in Martin's narrative, Book Sansa is still in hiding at the Vale, going by an assumed name—Alayne Stone—to avoid detection from Lannister sympathizers. But the show isn't being quite so subtle: There, Sansa's identity is an open secret, and she's found herself roped into an engagement to the sadistic Ramsay Bolton—son of the man who personally murdered Sansa's brother Robb at the Red Wedding. Ramsay's wedding is a plot point in the books as well, but there, he's set to marry a girl posing as Arya Stark. Why the shift? "We really wanted Sansa to play a major part this season," Benioff told EW. "If we were going to stay absolutely faithful to the book, it was going to be very hard to do that. There was a subplot we loved from the books, but it used a character that's not in the show."
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There's a small host of characters who are dead on Game of Thrones but (as far as we know) alive in the books, including quasi-prophet Jojen Reed, Jon Snow's pals Grenn and Pyp, Dany's onetime suitor Xaro Xhoan Daxos, and Mance Rayder, king of the Wildlings. The death that may have the biggest impact on the story going forward, though, is that of Barristan Selmy, Dany's trusted advisor and a point-of-view character who still has story waiting for him in Martin's as-yet-unreleased sixth Song of Ice and Fire novel, The Winds of Winter. Given the fact that Barristan lives in the books, even actor Ian McElhinney was surprised to find that he got axed in the show: "I'm disappointed," he told EW. "But I think you have to accept—as I have accepted—that the demands of TV are different than the demand of book writing. With TV there's a pressure to create a number of high points. One of the big things about this series—it's true in the books and even more true in the series—is the surprise element, the shocks. They've got to keep that up because people expect that."