Jelna Flarestar pioneered the Galaxy Patrol System's Cosmo Police as their first recruited esper, later shifting to a primarily administrative role. Her background features significant military service, commanding the elite Esper Commandos during the Great Galactic War against the Andromeda Rebel Army. This conflict culminated in her defeating the enemy leader, an act that resulted in her death during the operation.

She possesses a familial connection to Justy Kaizard, having raised him from childhood after discovering him in a shipwreck on the planet Sapphire. While their relationship began with a sisterly dynamic, it later evolved beyond this, though unresolved in the narrative. Following Justy's adoption of Astaris Vega, the orphaned daughter of an esper criminal he defeated, Jelna participated in Astaris's upbringing alongside Justy. She managed Astaris's status as a technical prisoner of the Cosmo Police, facilitating her integration into their household where Astaris was treated as a younger sister.

Within the Cosmo Police, Jelna maintained a close professional association with Bolba, another officer who held an older-brother-like relationship with Justy. Despite her desk-oriented duties, she retained operational awareness, particularly concerning missions involving esper criminals that implicated Justy or Astaris. She possessed orange hair and lilac eyes. Her narrative arc concludes with her wartime sacrifice, leaving her relationships and responsibilities within the Cosmo Police unresolved.