Question: What character is initially introduced in 1996's "A Game of Thrones is played by Hafþór Júlíus "Thor" Björnsson ?
{'answer': 'Gregor "The Mountain" Clegane', 'supporting_facts': [['Hafþór Júlíus Björnsson', 0], ['Hafþór Júlíus Björnsson', 1], ['Gregor Clegane', 1]]}