It would be easy to underestimate Valeriy Zaluzhny. When not in uniform, the general prefers T-shirts and shorts that match his easygoing sense of humor. When he first heard from aides to Ukrainian President Volodymyr Zelensky in late July 2021 that he was being tapped to lead the country’s armed forces, his stunned response was, “What do you mean?” As it sank in that he would become commander in chief, he tells TIME in his first interview since the Russian invasion began, he felt as if he had been punched “not just below the belt but straight into a knockout.”...