His father spread the word that his son was extremely intelligent, speaking before he was a year old. When he was two years old, an International Fleet officer came to test him for Battle School, and he was given a Monitor. His father was very proud of this recognition, and swore to give Bonzo everything he desired.
When Bonzo began to spend more time with his mother, Amaro expressed to his son that he was missing time with him. This caused Bonzo to begin to spend all his time with his father, and he realized that he was the one in control of the household. While he did not tell this to anyone, he wrote it down and threw the paper away. However, the International Fleet saw what he wrote through his Monitor, and the officer returned to speak with Bonzo about it. The officer discussed what Bonzo had realized with him, and Bonzo expressed his desire to remain at home and not go to Battle School in order to stay with his parents.
Bonzo decided to study what made his parents happy, and eventually noticed that on various days of the week his father traveled somewhere where he refused to take Bonzo with him. Curious, one day Bonzo decided to secretly follow his father to wherever he was going. His father reached a door that led to an apartment and unlocked it, leaving Bonzo behind. He didn't understand, and when he returned home he asked his mother about it. This shocked her, and she left to her room and cried.
Later, she put a note on the table addressed to Amaro, took Bonzo in the car to the train station, and rode to his grandmother's house. They stayed there for several days, with Amaro visiting twice to attempt to talk to his wife. A week later, Bonzo and his mother moved back in with Amaro, but his parents talked very little with each other from then on.
After overhearing a crude joke at the playground, Bonzo realized what his father had done, and saw that he had no honor. This changed Bonzo's entire perception of life, and when the International Fleet officer returned, he chose to go to Battle School.
As commander of Salamander Army, he suddenly had Ender Wiggin thrust upon him when Ender was promoted from his launch group. Bonzo was forced to give up a veteran soldier (a toon leader) to make room for him.
When he ordered Ender to stop practicing with launchies, Ender antagonized Bonzo by privately threatening to have Bonzo iced if he does not rescind the order. Ender unintentionally made the situation worse by trying to be gracious and offering Bonzo a means of saving face in rescinding the order. This just made Bonzo hate Ender more, as he became humiliated. When Ender entered battle with Leopard Army and fires his gun, turning a defeat for Salamander Army into a draw, Bonzo was further infuriated. Bonzo later announced that he traded him to Rat Army, and slapped Ender for disobeying his orders not to fire his gun. Ender surmised that this would backfire on Bonzo, for he will surely lose the respect of his soldiers when they see how he rewarded his "disobedient" underling for turning a defeat into a draw.
Bonzo was later provoked beyond all endurance when Ender, now commander of Dragon Army, defeated Salamander Army in a battle. Ender, enraged at the Battle School teachers, inadvertently humiliated Bonzo again in what was supposed to be the end-of-battle ceremony.
Later, Bonzo and a group of his lackeys cornered Ender in one of the Battle School showers. Trapped, Ender managed to shame him into engaging him in one-on-one combat. Evading him with the slipperiness of his still-soapy skin, Ender quickly ended the battle by hitting Bonzo in the face with the back of his head as Bonzo attempted to avoid an expected attack to his groin. Unknown to Ender at the time, this attack killed Bonzo.
Ender in Exile
Ender never truly realized that he killed Madrid until he saw Hyrum Graff's court martial, where the prosecution used 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 failed against Graff's defense, which includes running the same videos unedited.
Bonzo placed honor before all else, due to his father's extramarital affair during his childhood. He became infuriated when he was shown up, especially by Ender, who was younger yet much smarter than Bonzo. He was shown not to be a great leader, as Ender stated many times. It was proven that most of Dragon Army had better tactical and strategic skills than Bonzo.
Like most students in Battle School, he used a variety of slang terms, mainly words with Spanish origins.
- " I won't have any soldiers in Salamander Army hanging conchudo around with Launchies. You're a soldier now."
- — Ender's Game