Your identity is not only how you see yourself, but also how other people see you. Finding your identity is complicated enough for a human, but if you're a human/robot/artificial intelligence hybrid, things suddenly reach a complexity of epic proportions. From the beginning of Hyperion, its characters are labeled: the Soldier, the Scholar, the Poet, and so on. It's easy to let these labels affect your perceptions of the people behind them, and the stories reveal their true natures.
Then there's Johnny. Poor Johnny isn't even sure who or what he is, because he's a cybrid—a combination of human DNA and pre-programmed memories, in this case of a long-dead poet. Yeah, that can be a little confusing. We'd love to say that figuring out his own identity lies within his own hands, but it doesn't. It lies with Brawne's neck. To figure out how, you'll just have to read The Detective's Tale.