"Who am I?" is the most aggressively confronted question in All Quiet on the Western Front. Our narrator discovers his own identity as he grows from a naïve youth to a wizened front line fighter. He defines himself in many ways, mostly relative to other people and their ideas. He lauds "salt of the earth" type people, like his friend and mentor Kat. He is repulsed by men with no identity (i.e., those who define themselves by the uniform they wear rather than the content of their character). In an odd way, our narrator stays naïve throughout the book, hopeful to the very end, because he continues narrating. Had he truly given up hope for self-actualization, he would have stopped telling his story.
Paul holds onto his identity until his death.
Paul loses his identity long before this novel begins.