CZ-1 was a tutor droid named after its model. It was owned by the Kyrell family, who resided on the planet Jelucan. Its primary function was to tutor Thane Kyrell as a child during the years after the Galactic Empire was formed. By this time, the droid was very old and would make a great deal of effort to move.
CZ-1 was a tutor droid who served the Kyrell family as a tutor to Dalven and Thane Kyrell. When Thane was thirteen years old, CZ-1 supervised the teenager as he sat a mathematics test. When the boy remarked that he was late for his flying lesson, CZ-1 responded that he had to complete his lessons in order to master the subject and follow his brother Dalven into the Imperial Academy.
Thane toyed with prying lose the droid's restraining bolt but instead opted for using persuasion as a tactic. Thane told CZ-1 that he would not be able to gain admission to the Imperial Academy if he could not practice with flying. When CZ-1 responded that Thane's family had its own hangar and aircraft which mean he could practice anytime, Thane responded that he also had CZ-1, which meant that he could take math lessons anytime. Since he could only partner when his friend Ciena Ree was free and because she was coming on that day, he reasoned that it was better for him to prioritize flight time. As an added incentive, CZ-1 bribed the droid by offering to give him a lubrication bath.
After considering Thane's offer, CZ-1 accepted the boy's offer of a lubrication bath since his couplings had been stiff. After promising to be home that night, Thane agreed to continue his mathematics lesson the following day. Thane then went to practice flying with Ciena in his older brother Dalven's V-171 airspeeder.
By the time that Thane and Ciena were fourteen, CZ-1 accompanied the two children for a history lesson at their hideout, the Fortress. The tutor droid complimented Ciena for her knowledge of the history of the Clone Wars. However, the droid then added that she should be more worried about her calculus; something that upset Ciena. When Thane remarked that he should have installed the tact upgrade, the ancient droid responded that his job was to educate them. He added that Thane had smuggled him into the ridgecrawler in order to bring him here for study sessions and to ensure that they pass their entrance exams for the Jelucan preparatory academy. CZ-1 argued that a tact-upgrade would prevent him from educating them.
When Ciena groaned in despair, Thane encouraged her. With CZ-1's help, the two children passed their entrance exams and were accepted into the Jelucan preparatory academy. Following that, the two teenagers were successfully accepted into the Royal Imperial Academy on Coruscant and subsequently joined the Imperial Navy.
CZ-1 was an elderly tutor droid who was programmed to teach children various subjects including mathematics and history. According to Thane Kyrell, he had an unusually sly personality and was also good at debating. However, Thane was able to reason with him and even bribed him on one occasion to allow him to practice flying. At times, CZ-1 could be blunt and was known to lack tact in conversation due to his obsession with carrying out his duties as a tutor droid. As a droid, he enjoyed a lubrication bath since it relaxed his couplings.
CZ-1 first appeared in Claudia Gray's 2015 young adult novel Lost Stars, which was released as part of the Journey to Star Wars: The Force Awakens. His lines are told through the point of view of Thane Kyrell, one of the main characters of the novel.