 As the story reaches its climax, the antagonist is
When nobody aboard ship remembers where it's going, how can they tell when it has arrived? But ever since the engines somewhere in the rear of the world had changed their tone, from the steady whining Rikud had heard all twenty-five years of his life, to the sullen roar that came to his ears now, the feelings had grown. Instead, there was more of the blackness, and one very bright star set apart by itself in the middle of the viewport. But it came again, and each time it left him with a feeling he could not explain. Rikud knew that something which he could not explain had entered the elder man's head for a moment, but it had departed almost before Chuls knew of its existence. But something soft had cushioned the impact—something which had come into being just for the moment and then abruptly passed into non-being again, something which was as impalpable as air. The people had decided that they did not know where they were going, or why, and that it was unfair that the elders alone had this authority. Rikud often thought of his own death, still seventy-five years in the future, not without a sense of alarm. All the stars were paler now than before, and where Rikud had seen the one bright central star, he now saw a globe of light, white with a tinge of blue in it, and so bright that it hurt his eyes to look.
 Crifer, the only person Rikud ever thought of as a companion.
 Wilm, who appeared out of the blue.  The garden, because it holds so many evils for the characters as they enter.  Chuls, as it had been from the story's rising action.  Crifer, the only person Rikud ever thought of as a companion.