Bonzo is described as a strikingly beautiful boy of aristocratic Spanish lineage from the town of Cartagena. As commander of Salamander Army, he suddenly has Ender thrust upon him when Ender is promoted from his launch group. Bonzo was forced to give up a veteran soldier (a toon leader) to make room for him.
When he orders Ender to stop practicing with launchies, Ender antagonizes Bonzo by privately threatening to have Bonzo "iced" (that is, expelled from Battle School) if he does not rescind the order. Ender unintentionally makes the situation worse by trying to be gracious and offering Bonzo a means of saving face in rescinding the order. This just makes Bonzo hate Ender more, as he becomes humiliated. When Ender enters battle with the Leopard Army and fires his gun, thereby turning a defeat for Salamander army into a draw, Bonzo is further infuriated. Bonzo later announces that he has traded him to Rat Army, and slaps Ender for disobeying his orders not to fire his gun. Ender surmises that this will backfire on Bonzo, however, for he will surely lose the respect of his soldiers when they see how he rewards his "disobedient" underling for turning a defeat into a draw.
Later, Bonzo is provoked beyond all endurance when Ender, now a commander, defeats Salamander Army in a battle. Ender, enraged at the Battle School teachers, inadvertently humiliates Bonzo again in what is supposed to be an end-of-battle ceremony. Later, Bonzo and a group of his lackeys corner Ender in one of the Battle School showers. Trapped in the showers, Ender manages to hold Bonzo's Spanish honor over his head and shame him into engaging him in one-on-one combat. Evading him with the slipperiness of his still-soapy skin, Ender quickly ends the battle by hitting Bonzo in the face with the back of his head as Bonzo attemps to avoid the expected attack to his groin. Bonzo is sent home to his family in a body bag on the same shuttle that transports Ender back to Earth on shore leave. Ender never truly realizes that he killed Madrid until he sees Hyrum Graff's court martial, where the prosecution uses excerpts from videos of the fight in an attempt to prove that Graff's training program for Ender was murderously abusive, and that Graff had therefore exceeded his authority and contributed to the corruption of a minor. This argument ultimately fails against Graff's defense, which includes running the same videos unedited.
The Bonzo incident is pivotal in Ender's development, as it forces him to realize that he must fend for himself at all times, as the teachers refuse to offer him help—an attitude fostered by Graff. Believing isolation was the environment under which Ender would become the military genius needed for the Third Invasion, Graff attempts to put a psychological barrier between him and the other Battle School students at every opportunity. Despite this goal, he never intends to endanger the life of any student of the Battle School. By forcing Ender to take on Bonzo alone, without any adult intervention, Graff makes a mistake that stays with him through the rest of his career, one he continues to think of when making future decisions, and validating his own work.
Bonzo is also the main character of a short story, released in the second issue of "Orson Scott Card's Intergalactic Medicine Show", called Pretty Boy. This short story, taking place before Ender's Game, explores Bonzo's childhood, detailing some of his family life and some events that contribute to his sense of honor and eventual downfall.
Bonzo places honor before all else. He is infuriated when he is shown up, especially by Ender, who is younger yet much smarter than Bonzo. He is shown not to be a great leader, as Ender states many times. It is proven that most of the Dragon Army have better tactical and strategic skills than Bonzo.
- He feels a lot of hatred towards Ender, and he also has the desire to kill him.
- Stilson's death foreshadows Bonzo's. After Ender beats Stilson he says "You might be having some idea of ganging up on me. You could probably beat me up pretty bad. But just remember what I do to people who try to hurt me. From then on you'd be wondering when I'd get you, and how bad it would be."
- Bonzo is the only student in Ender's Game ever shown to be aware of sexual matters and how they might complicate military discipline. This is subtly implied in his order, relayed to Ender through one of the soldiers in his army, that no one is to be unclothed while in close proximity to his female soldier Petra. Ender's own innocence in this regard is indicated in his mistaken belief that Bonzo gave this order merely to isolate and ostracize Petra, and analysis that the order was "Stupid stupid."
- "I won't have any soldiers in Salamander Army hanging conchudo
- around with Launchies. You're a soldier now." - Ender's Game