Jun Jun is a member of the Amazon Quartet who serve Zirconia and Queen Nehelenia. She is the second youngest, and a tomboy. She is the acrobat of the Dead Moon Circus. She attacks by hitting bombs at her enemies with a baseball bat. Like Fisheye, her followers were always male. Indeed, two of them, Pakupaku and Biribiri, resemble fish. She can also create illusions. She possesses a dark green orb.
Jun Jun made two separate attempts to find Pegasus. After the Amazon Quartet were defeated by the Sailor Scouts, they switched Rini around with a doll (taking her away from Queen Nehelenia, who had her trapped) so they could ride Pegasus and take his horn. When Zirconia found out, he trapped them in another dimension inside mirrors, and they began to question if they were on the right side. Zirconia later teleported them to the place where he fought the Sailor Scouts and drained their power to increase his power, but this was stopped when Jun Jun, along with the others, smashed her orb on the ground, releasing her from Nehelenia's power and giving up eternal childhood.
The Amazon Quartet helped Sailor Moon fight Queen Nehelenia by switching the Golden Crystal (which was in Nehelenia's possession) with a pineapple. After Nehelenia was defeated and left Earth, the Amazon Quartet decided to leave somewhere, saying they might see the Sailor Scouts again.