Premise: A Game of Thrones is the first novel in A Song of Ice and Fire , a series of fantasy novels by American author George R. R. Martin . Ser Gregor Clegane , nicknamed The Mountain , is a fictional character in the A Song of Ice and Fire series of fantasy novels by American author George R. R. Martin , and its television adaptation Game of Thrones . Introduced in 1996 's A Game of Thrones , Gregor is the older brother of Sandor Clegane , from the fictional kingdom of Westeros .
Hypothesis: Gregor Clegane is a fictional character from the first novel of A Song of Ice and Fire.
Label: ENTAILMENT