As the final chapter comes to an end, Gene tells us about how his last year at Devon has affected his entire life- so much that, fifteen years later, he can retell all this pretty accurately. I think that he contradicted himself twice in that quote- for one, if you don't feel strongly about the enemy, they are not exactly your enemy at all. It might be his community's enemy, but since he "never developed an intense level of hatred" towards them, they are not his enemy. He contradicts himself more strongly, however, when he at first states that he never killed anybody, and then says just a sentence after that that he killed his enemy.
I don't believe that the real enemy of Gene was very apparent at all- at first I thought that it was his guilt, but he never killed it. His guilt would always be there- the belief that he had killed his best friend. And then, I thought: perhaps his enemy was the jealousy and envy he felt towards Finny. Even when Finny fell off the tree and broke his leg twice, Gene never truly let go of the resentment. At the end, however, when Finny died, Gene let go of the jealousy (partly, obviously, because there was nothing to be jealous of anymore), because the impact of the death made him realize that he didn't really have anything to be envious of.
Even if Gene harbored some sort of bitterness towards Finny, the 'golden boy' was always a part of Gene. Whenever something happened with Finny, Gene was really affected by it as well. When he mentioned Finny's funeral on page 194 (this was not in the Assignment 12 reading, but rather the page right before it), Gene said that: "I did not cry even when I stood watching him being lowered into his family's... I could not escape a feeling that this was my own funeral, and you do not cry in that case." It's clear from this bit of evidence how much Finny's death influenced Gene - he even felt that Finny's death was his own.
Why does this final chapter really wrap up the book? Who- or what- do you think was Gene's true enemy, if he even had one?