Characters significantly changed between books and TV series

Inherently, adaptation of any long series of novels will lead to certain characters being altered in the process of adaptation, or the actions of several minor characters will be condensed into one character. This it is entirely expected that details about several characters will be changed in the process of adapting author George R.R. Martin's A Song of Ice and Fire book series into the HBO TV series Game of Thrones.

However, fans who are watching the TV series who have not read the books may be confused by several changes or condensations, and may need a guide explaining in-context how these changes may affect the makeup of the narrative.

This article is therefore intended as a spoiler-free guide to TV-first fans about recurring characters that were significantly changed between the books and the TV series. It is not meant as an utterly comprehensive analysis of these changes for fans who have already read the books.

Defining "significant" differences in adaptation
There is no exact definition of what constitutes a "significant" overall difference in adapting a character from book to screen. There will always be some difference due to the process of adaptation, and the simple fact that certain characters who were POV narrators for hundreds of pages in each book have to be condensed down to 10 hours of television.

Certain characters have been renamed, or their appearance changed from the books, and these need to be explained to TV-first fans to avoid confusion. Certain minor characters may be "faithful" to actions in the books, but act as a condensation of several characters (i.e. rather than making five separate messenger characters, just having one character who delivers messages, etc.). One major example of this is that in the books, Davos Seaworth has four sons who serve in Stannis' army - Dale, Allard, Matthos, and Marc - all four of whom are killed in the Battle of the Blackwater. The TV series functionally condensed all four characters into one son, who retains the name, "Matthos Seaworth".

Moreover, some events happened "off screen" in the books, due to their third-person POV narration style, which the TV series chose to actually depict on-screen. This still does not necessarily constitute a "major change", as while they have no specifically corresponding scenes in the books, they still happened within the story. For example, the TV series contains scenes of Renly Baratheon and Loras Tyrell in Seasons 1 and 2, presenting them as lovers, but this was only alluded to in the TV series. Similarly, Margaery Tyrell was given significantly more scenes in the TV series, explicitly showing her motivations. None of this, however, is out of keeping with the books. The scenes at Renly's camp are told from Catelyn Stark's POV, and logically, she was never inside of Renly's bedchamber to witness scenes between Renly and Loras, or Renly and Margaery, in private.

Thus, only particularly drastic changes between books and TV series will be noted as "significant".

Ros
Ros the prostitute does not appear in the books, and is the first character created specifically for the TV show. However, some fans have speculated that her role is based on the "red-headed whore" who appears very briefly in the first novel. This is strengthened by the fact that Bianco was originally announced as playing "Red-Headed Whore". She was originally only supposed to appear in the first episode at Winterfell when Tyrion visits the local brothel. According to the episode's Blu Ray commentary, the producers were impressed with Bianco's performance, particularly that even though the shooting location was freezing cold at the time of her nude scene, she acted through it and gave no hint of discomfort due to the temperature in her performance. Ros' role grew as Season 1 went through production, and as it became a recurring role, author George R.R. Martin suggested that her character should be given a name.

Loosely speaking, Ros does stand in for, or act as a condensation of, several different prostitute characters that existed in the books. For example, in the books Cersei does imprison a prostitute that she thinks is Tyrion's lover (although his actual lover is Shae), but it is a different character named Alayaya, the daughter of Chataya, the woman who owns the whorehouse. The entire subplot involving these prostitute characters was cut from the TV series, and Ros functionally assumes this role in the story.

Martin has stated that he intends to work the character into later books in the series, probably as a throwaway cameo just to tie her presence into both the series and books.

Renamed characters
A few characters were renamed between the books at TV series, though otherwise, their behavior and actions were not significantly altered. The biggest example of this so far is "Yara Greyjoy", who is actually named Asha Greyjoy in the books. This was done to prevent confusion with Osha the wildling. Ironically, as the daughter of a Great House and one of Balon Greyjoy's only two surviving children, Asha Greyjoy is actually a much more prominent character than Osha the wildling; Asha Greyjoy is even a POV character in several chapters. Thus it is curious why they changed Asha's name and not the other way around. It is probably because Osha was already introduced in Season 1 and the similarity with Asha Greyjoy's name simply wasn't realized until production on Season 2 began.

"Robin Arryn" is actually named "Robert Arryn" in the books. He was named after King Robert Baratheon, but it was apparently felt that having too many characters named "Robert" would be confusing. The name "Robin" was picked because it allows him to keep his nickname of "Sweetrobin" from the books. In either case, the character is most often referred to by his nickname "Sweetrobin" anyway. Otherwise, the character is unchanged from the books.

Changes in appearance
In many ways, living actors will never make a perfectly exact, one-for-one match with the physical description of characters in a book series. Most of the actors in the TV series generally match the physical description of the characters they portray.

Certain characters, however, appear quite differently than they do in the books. For example, in the books, Syrio Forel is actually bald, but actor Miltos Yerolemou, who plays him in the TV series, has a full head of tall, frizzy hair. In the Blu Ray commentary, author George R.R. Martin himself said that he didn't care about such minor differences, being more concerned with the satisfying performance of the actor. Thus, such "cosmetic" difference are not very important.

Similarly, in the books, members of House Targaryen have a unique set of features inherited in each generation, possessing silver (platinum-blonde) hair and purples irises. The TV series actually tried having the actors use purpose contact lenses early in production, but quickly abandoned their use, partially do to the logistics of matching up the contact lenses in every location shot, and because they felt it "actors act with their eyes" and the colored contacts affected the emotion of their performances.

Another small change is that in the books, "Asha Greyjoy" is described as having short black hair, a lean build, and a sharp beak of a nose. In the TV series, "Yara Greyjoy" has blonde hair. Again, other than these minor naming and cosmetic differences, Gemma Whelan's portrayal is actually quite faithful to Asha Greyjoy's behavior and actions in the books.

Changes in character age
One of the initial changes between the books and TV series is that several of the younger characters have been aged-up. This was inescapable in a modern television production. As Westeros is a medieval society, its people have no concept of "adolescence". Girls become "a woman" and fit to marry as soon as they menstruate, and boys instantly become "a man grown" when they reach 16 years old. Several of the younger characters are depicting having sex at age 16 or earlier in the books. Because the TV series is primarily filmed in Northern Ireland, it is subject to the United Kingdom's decency laws for broadcasting, and the legal age of consent in the UK is 16 years old.

Much of the decision to age-up the younger characters hinged on Daenerys Targaryen specifically. To begin with, while some of the other teenaged characters have sex later in the books (i.e. Robb Stark has sex at age 16 then marries the girl), Daenerys explicitly has a sex scene on her wedding night in the very first episode. This instantly grabbed the attention of UK censors, so Daenerys had to be aged-up. However, Daenerys' age is inherently linked to the timeline of the series, because her mother was pregnant with her when Robert's Rebellion ended and her father the Mad King died. The TV series increased Daenerys' age by two years to be fifteen years old in Season 1, but this meant that Robert's Rebellion accordingly had to be pushed back two years. This affected the age of other children who were born to characters returning from the war, i.e. Robb Stark and Jon Snow were were newborn infants immediately after the war ended. Thus, to keep the chronology and character relationships intact, most of the child characters were aged-up, usually by roughly two years.

Keeping in mind that in medieval times the age of maturity was lower than it is today, this younger age in the books isn't quite as unusual as it sounds. Robb Stark is "on the cusp of adulthood" when the story begins, which in the fantasy world of the books is defined as "almost 16", but to a modern TV viewing audience is defined as "almost 18", etc. So in many cases, this simply makes it more appropriate to a modern audience's sensibilities, due to age differences in a medieval society. Still, this can at times lead to some discrepancies with some of the younger characters: when Joffrey Baratheon torments Sansa Stark in Season 2, he is portrayed as being about 15 years old, while in the second book, he is 13 years old. Thus, Joffrey's torment of Sansa doesn't have quite the same inherent sexual tension to it in the books, because they're both two years younger.

Another way that character ages are affected by UK decency laws is that they rules are very specific. According to the rules for underaged nudity in UK broadcasts, what matters is how old the character being portrayed is, regardless of the actor's actual age in real-life. In other countries with different decency laws for cinema, a 22 year old can portray a 15 year old character in a nude scene, albeit unconvincingly. Such is not the case in the UK. Sansa Stark is only 11 years old in the first book, making her 12 years old during the second book, and because Sansa has been aged-up in the TV series, this makes her 14 years old in Season 2. In episode 4 of Season 2, "Garden of Bones", King Joffrey Baratheon has his guards beat and strip Sansa in front of the entire court. The TV series scene, however, had to be drastically toned down: in the book, her gown is quickly ripped off down to the waist, and she is left covering her breasts with her hands as Ser Meryn continues to pound away at her bare flesh with his sword. Even though actress Sophie Turner, who plays Sansa, had actually turned 16 a few months before this scene was filmed, "Sansa Stark" - the character being portrayed - was still only 14 years old, and thus UK decency laws restricting depicting of under-aged nudity still applied.

An unrelated change was the decision to increase the age of major character Margaery Tyrell, who is slightly older in the TV series than she is in the books. At the time of her marriage to Renly, in the books Margaery is sixteen years old (making her the same age as Robb Stark). As with most teenage characters, Margaery's age has been increased in the TV series, and viewers must keep in mind that 16 was the age of adulthood in medieval societies. Even so, Margaery is still slightly older than Robb Stark in the TV series, as Natalie Dormer is four years older than Richard Madden (who plays Robb). The TV series producers enjoyed Dormer's audition so much that they decided to overlook this minor difference, which does not significantly change her character.

Overall, while some characters have had their ages slightly changed for the sensibilities of modern audiences, or because of a preference for a specific actor whose age was different from their character's by a few years, there has been no particularly significant change in the age of any established characters.