 As the story reaches its climax, the antagonist is
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. 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. Something loomed there in the port, so huge that it spread out over almost the entire surface. A section of it had expanded outward and assumed the rectangular shape of the viewport, and its size as well.
 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.