She was given a dark green orb by Queen Nehelenia, which gave her more power, and eternal childhood.
She is the acrobat of the Dark Moon Circus, and the second youngest of the Amazon Quartet. She is also a tomboy.
Jun Jun always seemed to be fighting Sailor Jupiter.
The Amazon Quartet were eventually defeated by Sailor Moon, and later trapped in another dimension by Zirconia after switching the captive Sailor Mini Moon around with a doll. Here they began to realize Zirconia's side was the wrong side. Zirconia drained their power, but they eventually smashed their orbs, giving up Nehelenia's power and eternal childhood. They later took the golden crystal from Nehelenia and gave it to Sailor Moon.
Her final appearance was in the final episode, leaving quietly with the others while Pegasus returned to Elysion.
Junjun attacks by hitting smaller green orbs (which are really bombs) at her enemies with a baseball bat. She also can create illusions.