Even as the rakshasa derided the king and his dynasty, Anaranya issued a curse that Ravana would meet his end by one of his descendants from the same dynasty. This curse comes true when Rama defeats Ravana.
As the rakshasa scorned the monarch and his family, Anaranya uttered a condemnation that Ravana's fate would be sealed by one of his own kin from the same royal line. This prediction comes to pass when Rama triumphs over Ravana.