Roy Hobbs is a naturally gifted baseball player. The only thing bigger than his talent is his ego. Roy doesn't just want to excel at baseball, he wants to be the best player that ever lived. As a teenager, this attitude gets him shot by an insane woman targeting great sports players. He is out of the game for 15 years before returning as a rookie at the age of 34. Roy hasn't learned the lesson of humility during his time away from the game. In fact he seems more determined than ever to smash every baseball record in the books; he plays solely for himself, not the team. Roy wants the best of everything for himself—the highest salary, the most awards, the most beautiful woman—ignoring other opportunities for real happiness. Although a moral player, Roy is tempted into throwing the final baseball game of the pennant race for a check large enough to woo the woman of his dreams. By the time Roy realizes the world is larger than his personal dreams, it's too late. He loses the game, the girl, and his self-respect.
Memo Paris is a beautiful woman whom many men, including Bump Bailey and Roy Hobbs, chase after. Although beautiful, Memo is a destructive force in men's lives, including Roy's. She negatively affects his game, health, and future. From the beginning it is clear Memo doesn't really love Roy, yet she leads him on. At first Memo simply appears to be using Roy for money and attention, but her motives become more sinister as the novel progresses. In the final chapters, it appears Memo has helped poison Roy and encourages him to "fix" the final game if he wants to marry her. Everything is for her own gain, of course, and she admits to having always hated Roy. Memo is a desperate woman who values wealth above all else. She is the embodiment of the scriptural quotation, "Money is the root of all evil."
In the Arthurian references found in The Natural, Pop Fisher is a stand-in for the Fisher King, an aged king whose health is tied to the well-being of his land. The Fisher King seeks the healing power of the Holy Grail, just as Pop Fisher chases the healing power of the elusive pennant. When the team is doing well, Pop's health improves; but when the team is doing poorly at the end of the novel, he looks aged and near death. Pop is a tragic figure because his dreams are tied to Roy's performance, which means success or failure is out of his hands.
While Memo is a life-sucking force for Roy, Iris is life-giving. Her name, Iris Lemon, conjures images of vast gardens or lush fields, which is appropriate given her fertility. She gave birth as a teenager and at the end of the novel is pregnant with Roy's child. She offers love and emotional nourishment, while Memo offers poison, both literal and emotional. Despite Iris's ethereal qualities, Roy rejects her because she isn't as beautiful as Memo, ignoring the spiritual and emotional happiness Iris offers.