Ender's Game is a 1985 science fiction novel by Orson Scott Card. The novel is set in the future where humanity has barely managed to survive a series of attacks by an alien race known as the Formics.
Anticipating another attack, a school has been set up to train the most gifted children in the art of war. The school is known as Battle School and it is there in the zero gravity training sessions that the protagonist, Ender Wiggins, demonstrates great aptitude in warfare tactics.
Like Thomas, Ender demonstrates abilities far beyond those around him. Later in the novel he completes what he believes is a simulation mission, destroying the Formic homeworld and winning the war. After completing the mission, he learns that it was not a simulation but the real thing. He has just exterminated an entire race. Ender is racked with guilt over this and enters into a deep depression. This echoes aspects of Thomas's own life. He is racked over guilt when he learns that he was involved in the planning of the Maze.
The violence perpetuated by Ender in the novel is the subject of much debate amongst critics and scholars alike. Some feel Ender is too violent to be considered heroic, while others feel the violence simply reveals humanity's darker aspirations, particularly when the situation is so unique. The children in Ender's Game are placed into warfare training at a young age, much like the Gladers are being tested for their ability to endure harsh conditions and work together to solve an unsolvable problem.