NANA ASAHINA:

Nana Asahina was a freelance tabloid photojournalist who appeared only in episode 043 of the anime. She often did work for the sleazy tabloid "Surprise," which Sailor Venus noted was known for publishing any story, regardless of truth. According to her business card, Nana was a member of the World Photographer Association, the New World Pen Club, and the World Photo Club Academy. After a bit of research, Artemis found out that Nana had recently sprung to fame seemingly overnight and was getting scoops in every field. He speculated that she may have been turned into a youma by the Dark Kingdom. His suspicians turned out to be correct: she had been transformed into the youma Oniwabandana by Kunzite.

Kunzite was using Nana/Oniwabandana to investigate strange abnormal energy bursts which have been happening in the Dark Kingdom. After a few days of investigating, Oniwabandana showed Kunzite and Queen Beryl two photographs of the Sailor Senshi depicting Sailor Moon fighting against the other girls. She believed that the fighting was the source of the abnormal energy bursts, although Queen Beryl openly wondered if it was actual infighting or a trap. Kunzite was unsure as well, so Oniwabandana was given additional time to continue her investigation. After being given additional time, Oniwabandana immediately staged a robbery of Jewelry Osa-P in order to lure the Sailor Senshi onto the scene. The plan worked, and the girls arrived, at which point she quietly transformed back into Nana and began bombarding them with questions. They gave her no information, so she similarly harassed Naru and Usagi the next day (due to Naru's involvement in the robbery).

The infighting among the Senshi was actually a ploy to get Sailor Moon into the Dark Kingdom's lair. After Artemis shared his suspicians about Nana with the girls, they decided that it was time to implement the final phase of their plan. Usagi took a note to Nana's condo which read, "I want to quit being a Sailor Senshi of love and justice. I don't want to fight with those other Senshi anymore. I want to make a shocking confession, so I will be waiting at the Juuban Cemetery at 11:00 PM tonight." When Nana took the letter back to Kunzite as Oniwabandana, he decided that it is time to go out there. They met Sailor Moon at the cemetery, but quickly saw through the girls' plan when Oniwabandana heard the other Senshi hiding in the bushes. The youma quickly attacked Sailor Moon and the other Senshi ultimately arrived on the scene to help their friend. After a short battle, Sailor Moon used Moon Healing Escalation to heal Oniwabandana, causing her to transform back into Nana. Nana was temporarily unconscious, but when she awoke, the Senshi were still on the scene. She presumably remembered nothing about being a youma, because she began frantically asking the girls about rumors of the Senshi breaking up.

Nana Asahina's seiyuu was Miyako Endou.

See also:
Episode 043 - Usagi Going Alone? The Sailor Soldiers' Big Fight
Miyako Endou
Oniwabandana