Character Analysis
As Bart's bully and nemesis, Tyro Bergen is a major figure in our main man's life. Technically, he's supposed to be Bart's mentor (or "Big Brother") at Baileywell—but from Bart's very first day, Tyro antagonizes him for no real reason. Lucky Bart.
What's interesting is that we, as readers, don't know much about Tyro apart from his bad behavior. We know that he's a "star" and the "school celebrity" (5.4)—"tall, thin, blond, and maybe just a little too handsome to pass for a regular kid. More like a movie star auditioning for the role of a prep school student" (4.7). We also know he's cruel and violent and mega wealthy. But beyond this basic info, Tyro's a bit of a mystery. Since Bart doesn't really know Tyro well, there are a lot of question marks.
A Few Deductions
Though Tyro is not a fully drawn character in the book, we often catch Bart wondering about what makes him tick. When Bart finds out Tyro's parents paid for his scholarship to Baileywell, he wonders if that's what's caused the bullying:
I was trying to figure out what this new information—meaning, new to me—might have to do with the way that Tyro had treated me […] Was bullying me his way of getting back at his mom and dad? Did he see me as some kind of competition? What did he have to complain about? Too much money? Too much power? (9.33)
Of course, Bart eventually finds out that Tyro's life isn't perfect. Tyro's sister Nola is sick in the hospital—so sick that she eventually dies. It's implied that this family tragedy at least contributes to Tyro's bullying. In fact, when Nola dies, Tyro starts a fistfight with Bart at school. He doesn't seem to experience any personal growth over the course of the novel, but then again, the novel isn't really about Tyro. It's about Bart.
Tyro Bergen's Timeline