What qualities does Ender have that make him a great leader?

Gives his opponent a brilliance and makes people hate him. The boys who faced him like Stillson and Bernard were threatened by Ender. Ender was chosen by the Colonel graph and the inner circle. He combines extraordinary intelligence and aggression, becoming a deadly soldier and an excellent commander. Ender is always breaking other companies in a simulation battle. Other juvenile leaders realized that Ender was a threat

Colonel Grave is ready to make Ende burst Burgess through cruel training. He constantly forced Andel to do himself physically and mentally exhausting things; he thus indicated the quality of commanders they needed. Colonel Graf uses games to manipulate, train and evaluate Ende. If it is not a graphic violent strategy, you can say that Ende is not as good as a commander. Colonel Grave maximizes Ander's tactical skills, even though it often causes pain and frustration

Colonel Graf is the head of the battle school, Ende was trained for the first time. He is one of the hero who influences Ende. Colonel Graf was very good for him when Ander first arrived at the combat school, so the other children hated Ander. Graff intentionally isolated Ender, and Ender's loneliness and isolation was an important part of his development. When Ender completes a task it becomes a more difficult task. This makes Ender a creative, independent and powerful one. Ender was driven to the limit by the government and became a great military leader, and he understood all the features of the great leader.

Bien faces Ende and asks for becoming a leader of the platoon or "Champ Leader". Ender tells him that if he prove that he is a soldier he will become a toon leader. So Ender wants to know why he picked out the bean. Then he realized that his approach to Bean is the same as what Graff did to him three years ago. Ender understands that the graph isolated him and made him the best soldier. But even if his soldiers did not know, he decided to become a friend of Bien.