Rusalka Evereska hails from a small Northern European village. Witnessing a red aircraft crash-land nearby inspired her to pursue aviation. She enlisted in the military before the Pillars appeared, starting as a conventional soldier before shifting to become a fighter pilot following heavy conventional losses against the Pillar threat. During "Winged Day," she survived solely because the first Valkyrie, Amy, sacrificed herself to save her, leaving Rusalka as the last Valkyrie. This event deeply affected her, cementing her resolve to become a Valkyrie and defend humanity. Her military career saw steady advancement: from captain leading a small squadron, she rose to major, then lieutenant colonel, and ultimately colonel. As colonel, she commanded the entire Sigrdrifa Unit, directing strategic operations across multiple regions. Her leadership included developing innovative Valkyrie squadron tactics later adopted globally, significantly boosting combat effectiveness against Pillars. Physically, she possesses long silver hair, blue eyes, and stands 166 cm tall, often noted for a graceful yet strong presence. Her personality blends high intelligence with a strict, disciplined command style. This rigidity sometimes caused misunderstandings, though her subordinates recognized her dependability and deep commitment to their safety. She led with tough love, prioritizing mission success and team cohesion. As a pilot, she flew a bright red Supermarine Spitfire Mk. IX. While not the most advanced Valkyrie aircraft, her exceptional piloting skills, tactical ingenuity, and extensive experience compensated, making her a formidable aerial combatant. Within her team, she maintained close professional bonds with subordinates like Senea Stingle, Victorica, and Canaan, who trusted her leadership despite exacting standards. Her command decisions included strategically reassigning Claudia Bruford to Tateyama Air Base. Her story spans multiple timelines: by age 19 in her light novel's first volume, leading her initial squad; at age 20 in the second volume, ascending to higher command; and at age 24 during the main anime series, appearing as a seasoned colonel coordinating Valkyrie deployments.