JunJun is an athletic tightrope walker and member of the Dead Moon Circus's Amazoness Quartet, serving under Zirconia and Queen Nehelenia. Impulsive and tomboyish, she often uses masculine pronouns and exhibits a vulgar, "yankee"-like demeanor. She possesses the darkest skin tone among her quartet sisters and ranks as the third tallest. Her circus role involves trapping targets in nightmares to extract Dream Mirrors, briefly letting them experience their dreams before attacking. Originally the future Sailor Juno, guardian of asteroid Juno, JunJun and her sisters slept within the Amazon Jungle until Queen Nehelenia forcibly awakened and corrupted them using nightmare energy. This brainwashing transformed them into the Amazoness Quartet. As JunJun, she wields a dark green Amazon Stone orb for attacks. During the Dead Moon Circus conflict, JunJun assaults the Sailor Guardians. She and her sisters battle Sailor Saturn and Sailor Chibi Moon inside their circus tent. As the quartet regains their senses due to Saturn's influence, Zirconia seals them in orbs within Queen Nehelenia’s mirror. After Nehelenia's defeat by Eternal Sailor Moon, the nightmare corruption lifts. JunJun and her sisters revert to their true identities as Sailor Asteroid Guardians—Sailors Ceres, Pallas, Juno, and Vesta. They return to suspended animation in the Amazon Jungle, awaiting their destined reawakening when Sailor Chibi Moon matures into a full guardian. Her primary manga attack is "Tama Gusuri" (Gem Medicine or Orb Medicine), utilizing her Amazon Stone. In the *Sailor Moon Eternal* film adaptation, this attack is reassigned to PallaPalla, leaving JunJun without a shown attack. Her characterization consistently emphasizes her athleticism, connection to the color green, and eventual restoration as Sailor Juno.