Programmed from the start as a soldier in the world of <Hero's Duty>, she has a grim and tragic backstory where she lost her husband to an attack by Cy-Bugs—the monsters of this world—on their wedding day. Furthermore, because this is part of her programming, her deceased husband can never be resurrected. Personality: Sergeant Calhoun possesses the personality of a typically tough and strict soldier. Thorough Perfectionist: She is extremely strict with her subordinates and is a resolute commander who does not tolerate mistakes. Cynical and Blunt: Due to the tragic past event of losing her husband, she has closed off her heart, often appearing cynical and expressionless. Responsibility and Loyalty: Though she seems cold on the outside, she hides a deep sense of responsibility and a warm heart (Large heart) dedicated to protecting her comrades and children. Hobbies: Military Training and Marksmanship: When not on the battlefield, she enjoys training her unit members or practicing at the shooting range, hitting the bullseye with every single round.

Mysterious creatures appearing in <Hero's Duty>. They appear as common mobs and mid-bosses in the work, resembling mechanical insects. They are unaware that they are game characters and are driven entirely by the instinct to consume and multiply. In other words, they are not just simple pests or predators, but a virus and a disaster itself. The name appears to be a portmanteau of Cyber + Bug.

There is also a massive individual species called the Queen Cy-Bug. Given that the design is similar to the Queen Alien, it seems to be an homage. She does not appear in the movie, but appears as the final boss in the game version that covers the aftermath. However, the difficulty level is notoriously high.