How does Ender and Shen become friends?

Ender and Shen become friends during their time at Battle School when they bond over shared experiences of being outsiders. Shen helps Ender by standing up for him against bullies, and Ender reciprocates by including Shen in his strategies and plans. Their friendship grows as they support each other in the challenging environment, highlighting themes of loyalty and camaraderie amidst competition.