Ender's Shadow (1999) is a parallel science fiction novel by Orson Scott Card with a plot covering some of the events in Ender's Game from the point of view of a supporting character named Bean. This book was originally titled "Urchin", prior to release.
He also makes friends with an older boy named Nikolai Delphiki who is drawn to Bean because of their similar looks. It is soon discovered, through Sister Carlotta's research, that the two boys are actually genetic twins, except for Bean's genetic enhancements. Back in the lab, the scientist Volescu had turned Anton's Key, which means Bean's body will never stop growing - including his brain - until a premature death between the ages of fifteen and twenty-five. Sister Carlotta manages to ensure that Bean will get to live with Nikolai and his parents after the war.
This story takes the reader through Bean's experiences in Battle School and shows how Bean, though apparently peripheral in Ender's Game, is much more important to the fate of Earth than he originally seemed. In addition, the book depicts the first of Bean's encounters with Achilles. At the very end of the story, Ender leaves on a colonization ship and never returns to Earth as part of a treaty. (After the war with the buggers, there is a war between several nations on earth. In the Locke Proposal, Peter Wiggin writes terms for a treaty, including that Ender will never be allowed on earth, as everyone fears he will become a general and other nations can use him to take over the world.)