Who is the antagonist in Death of a Salesman?

The antagonist in Death of a Salesman is Biff Loman. Biff is Willy's eldest son and the apple of his eye. However, Biff is also a disappointment to Willy. He has never lived up to his father's expectations and has failed to achieve any success in life. This causes a great deal of tension between Willy and Biff and ultimately leads to Willy's death. Biff's main character flaw is his lack of motivation and ambition, which prevents him from achieving his father's expectations and leads to Willy's tragic downfall.