"SWORD!"
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Ser Gregor Clegane is the head of House Clegane, a minor vassal house of House Lannister. Gregor is freakishly huge, said to be the largest man in Westeros, almost eight feet in height and heavily muscled. For this reason he is called "The Mountain That Rides" or, simply, "The Mountain". He is feared throughout Westeros with a reputation for ferocity and anger. He is a loyal retainer and servant of House Lannister, particularly to Lord Tywin.

vs.

"Where is it written that power is the sole province of the worst? That thrones are only made for the hated and the feared? You would be a wonderful king."
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Ser Loras Tyrell of Highgarden is a popular tourney knight and ranks as one of the most skilled knights in Westeros. He is commonly known as the "Knight of the Flowers", as a rose is the sigil of House Tyrell and he thus wears armor elaborately engraved with flowers. He was the lover of Renly Baratheon and supported his claim to the throne as commander of his Kingsguard. After Renly is murdered and believing Stannis Baratheon to be behind it, Loras has promised to avenge his death and has joined forces with King Joffrey and Tywin Lannister in the War of the Five Kings.

I really wish the original actor for The Mountain would've stayed on. He was a really intimidating character in his first appearance. The new actor is so lanky and unimposing.

Yeah the first guy left to play the main orc villain in The Hobbit