Game of Thrones ran for eight seasons. While few characters were lucky enough to survive through all of them, those who remained in the show for a long time tended to change. Some characters ended up nearly unrecognizable from who they once were.
This was the result of hours of slow and believable character development, that challenged the core behaviors and beliefs of a character. In other cases, the groundwork was not done beforehand, and the changes were considered to be jarring by fans. Nonetheless, plenty of characters had changes happen to them - for better or worse.
9 Tyrion Lannister Changes His Hopes And Allegiance
In Game Of Thrones' early seasons, Tyrion Lannister is a sympathetic character, giving more nuance to the War Of The Five Kings than if all of the Lannisters were thoroughly despicable. Tyrion is sympathetic, witty, and likeable. Most fundamentally he's loyal to his family, helping the war against the Baratheons and Starks.
Part of Tyrion's motivation is his desire to be accepted by his family, especially his father, as well as being despised by the other factions. His hopes of impressing Tywin are crushed after his father's return following the Battle Of The Blackwater. The subsequent betrayal from his family following Joffrey's death leads him to abandon that dream, and side with Daenerys Targaryen.
8 Bran Becomes Something Otherworldly
Something more than mere character development changes Bran Stark. Something within Game Of Thrones explicitly alters his personality. When he is first introduced, Bran is a curious, exploratory, kind young boy, who is very dedicated to those around him.
After his time North of The Wall, Bran becomes the new Three-Eyed Raven after the former's death. Although he still uses the name Bran, his personality becomes an amalgamation of all of those who came before him. As a result, he becomes far more dispassionate, more reserved, and less caring to those around him.
7 Jaime Almost Achieves A Redemption Arc
Jaime Lannister underwent one of the most subtle and periodic character arcs in Game Of Thrones, before a sudden snapback. Jaime spends season 1 as an antagonist and season 2 largely offscreen. Jaime gets his own story arc beginning with season 3, where his time with Brienne of Tarth, reunion with his brother, and own reflections see him become more moral.
After some time, Jaime becomes the sole voice of morality following Tyrion's departure, regaining his knightly honor, culimating in him facing the White Walkers alone when Cersei breaks her promise. Hailed by many fans as a fantastic piece of character development, it is a vast change. Until Jaime returns to Cersei to die beside her, calling himself "hateful".
6 Varys Becomes Complacent In His Deceptions
For Game Of Thrones' first six seasons, Varys stands as the chessmaster among chessmasters, head and shoulders above most of the other players. Under the nose of the Lannister regime, acting as a trusted servant, he promotes the interests of a new Targaryen regime, believing Daenerys the best hopes for the people.
In the later two seasons, Varys begins to slip. After seasons of ensuring that he is always safe, regardless of his deceptions, he spends season 8 undermining Daenerys to some of her closest advisors. With no contingency plan, Varys is executed for this complacency.
5 Arya Stark Becomes Composed And Lethal
Early in Game Of Thrones, Arya Stark is fierce, passionate, hot-tempered, and prone to acting first and thinking after. Even her first kill is in a fit of panic, stabbing a stableboy in the gut when she forgets everything she's learned about fighting.
Her time on the run, with the Hound and the Faceless Men, sees Arya master her own emotions, and become far more dangerous for it. Now knowing her own abilities and capablity of planning and patiently executing her own schemes, Arya becomes more controlled while retaining the core of her personality.
4 Theon Is Broken And Rebuilt
Theon is introduced in Game of Thrones as a disrespected character, who is looked down on by nearly everybody except his best-friendship and brotherly relationship with Robb. As a result, he acts superior and obnoxiously to compensate, with his insecurities leading to his worst acts in occupying Winterfell and murdering two peasant boys in cold blood.
With many viewers willing to despise him, Theon regains audience sympathy through the sheer hell he is put through by Ramsay Bolton. Theon's personality is nearly broken out of him. When he regains some sanity, he is still Theon Greyjoy, but a noticeably humbler, kinder, and more loyal person from it.
3 Cersei's Care For Her Children Slips
In the early seasons of Game Of Thrones, Cersei Lannister's love of her children is one of her most notable traits, commented by many characters to be one of her few decent qualities. Even with Joffrey, who she recognizes to be a monster, she can't help but love and protect.
This diminishes as Game Of Thrones continues and Cersei becomes a crueler person. Joffrey dying nearly breaks her, and whilst Myrcella's death devastates her, she recovers to seek awful vengeance. Tommen's suicide as a result of her actions ultimately barely fazes her, so detached that she simply begins wearing his crown.
2 Sansa Stark Learns To Play The Game
At the beginning of Game of Thrones, Sansa is a representation of the expectations of young noble girls. She excels at arts considered 'womanly' in Westeros, and dreams primarily of her marriage to a highborn man and having his children, without many other ambitions.
Her experiences in Game Of Thrones, the horrors she endures and the tutelage she receives from several awful people, see her become savvier, wiser, and more ambitious. Ultimately, she learns how to play the Game of Thrones, becoming good at it. Until, she leads the North to secede from the Iron Throne in the finale and rules it as its sole queen.
1 Daenerys Goes From Messianic To Monstrous
One of the most contentious plot points of the already-contentious eighth season was the sudden turn of Daenerys Targaryen. Although she had displayed a temper, and some messianic tendencies in earlier seasons, she remained stalwartly on the side of good throughout. Deanerys was one of Game Of Thrones' most sympathetic characters.
Rejection by Jon Snow, limited popularity in the Westeros, and the loss of loved ones see her snap while fighting in King's Landing and begin massacring civilians in the city with dragonfire. Although the twist could have worked, many considered it far too rushed, meaning Daenerys's sudden turn felt jarring and contrived.