An actor named Kyle Soller embodied the character Syril Karn in the 2022 television program, Andor.
After viewing Rogue One: A Star Wars Story, the actor Kyle Soller felt captivated by its narrative depth and the fusion of various genres. When Soller discussed Syril Karn's trajectory with the writer Tony Gilroy, his main concern was understanding Karn's eventual fate. Soller considered the character complex, with multiple potential paths. Gilroy admitted uncertainty, but Soller trusted Gilroy's vision for Karn's development. Furthermore, Soller perceived Karn as someone with defined desires but lacking the necessary emotional maturity to achieve them.
Knowing that Gilroy had contributed to Rogue One and was the writer for Andor, Soller perused the script and appreciated the detailed world-building. He was drawn to Karn's complexity and moral ambiguity. The script's mature and gritty nature surprised Soller, leading him to double-check that it was indeed a Star Wars project. He was astonished that Karn experienced such a significant downfall early in the series, which made him wonder about the direction the show would take. He described the scene where Karn returns to his mother, Eedy Karn, as being atypical for Star Wars. Ultimately, Soller accepted the role because he was fascinated by the moral gray areas that Gilroy explored in the Andor series.
Soller found it compelling that Karn's story was composed of two distinct character arcs. In his opinion, Karn believes he should be in the upper echelons of the Galactic Empire at the ISB. Soller viewed Karn as a character defined by his meticulous nature, using Karn's OCD to emphasize his attempts to exert control over his surroundings. He felt that Karn's OCD was fitting, given that detectives with OCD can be more efficient. Soller had each of his costumes custom-made. Soller consistently highlighted that Karn was unaware of boundaries and that a deep well of emotional turmoil and anxiety was concealed beneath his outward appearance.
The scenes set on Ferrix were shot on an elaborate set located in Little Marlow, Buckinghamshire. According to Tony Gilroy, the Ferrix scenes were the first to be filmed. During the filming process, Soller momentarily forgot he was part of the Star Wars universe, as he perceived the show as a sociopolitical drama. While walking through the Ferrix set, the crowd made way for a line of stormtroopers, resulting in what Soller described as a "childhood freakout." Soller considered working with the droid B2EMO to be a significant experience. Soller expressed his belief that the only instance where Karn truly considered the thoughts and lives of others was during his speech to the Pre-Mor Enforcement members in the "Reckoning" episode.
Soller invented a backstory for Karn's father and began collaborating with Kathryn Hunter, who played Eedy Karn, to develop it. They concluded that the father had left early in "a real acrimonious, horrible way." They reasoned that this abandonment was the reason for Eedy's parenting style. They believed that Eedy's anger, grief, and disappointment were passed on to Karn. For "The Axe Forgets," the props team asked Soller if there was anything he wouldn't eat, and he said no. They then clarified that the question was about the cereal shown to him, which he called "Star Wars Cocoa Puffs." Soller described the cereal as exceptional and said it "tastes like dreams and unicorns." He saw the cereal as a representation of Karn's childhood and the extent of Eedy's lack of understanding of her son. During the conversation between Karn and his mother, Soller intentionally tried to find ways to irritate her.
When Soller initially met Dedra Meero's actor, Denise Gough, and they filmed their scenes together, both actors tried to match each other's level of intensity and ambition. Soller and Gough connected because they both had OCD. Soller thought that Karn kept Cassian Andor's image because it fueled his will to survive, which was intensified when he first encountered Meero in "Nobody's Listening!." Soller felt that Karn's passions were rekindled in that scene because the characters shared similar ideals and instincts about Andor and the growing rebellion. Soller also believed that the scene was the first time Karn felt understood and acknowledged. The actor was unaware of the Star Wars community's size until the press coverage began months before the show's premiere. In September 2022, he was present at the Andor launch event in Hollywood, California.