Naru Osaka is Usagi's best friend.
Naru has wavy red hair that is slightly shorter than her shoulders and often wears a darker teal bow in her hair. She has teal eyes (unlike her blue-eyed manga counterpart). When she is not wearing her school uniform, she often wears solid-colored skirts and tops. Her school uniform usually has white socks and black Mary Jane shoes. Her normal outfit is that of an orange shirt, teal skirt, and sea green tights with black Mary Jane shoes.
From the very beginning of the show, Naru tended to be attacked by the Dark Kingdom as well as various Monsters of the Week. She always got caught in the middle of the Dark Kingdom's plans, first in episode one. Shitennou Jadeite's Morga locked Naru's mother away and impersonated her. She infested the jewelry sold at her jewelry store with dark energy to harvest human energy for the Dark Kingdom. Morga eventually revealed herself to Naru and attacked her, but Sailor Moon came in time to rescue her.
While Nephrite was on earth carrying out the plans of the Dark Kingdom, he had many interactions with Naru, to the point where she developed romantic feelings towards him. Nephrite came to regret his evil ways and became good after he too returned her feelings. Naru even went as far as protecting him when Sailor Moon tried to use her Moon Tiara Action to finish him off.
Zoisite didn't approve of this relationship and instead saw it as a serious betrayal to the Dark Kingdom. He sent monsters to kill Nephrite and though Naru tried her best to help him, Nephrite was eventually killed under Zoisite and he died whilst protecting Naru.
Naru was heartbroken after Nephrite's death, skipping school for over a week. Usagi convinced her to get over it and tried to substitute Umino as Naru's new interest. Though she heavily disapproves at first, Usagi managed to convince them to go out. After seeing Umino's heroic actions while he was impersonating Tuxedo Mask, she started to see him differently and they are seen to be together more often.
Naru at first doesn't know that Usagi is Sailor Moon and since she is not a Sailor Guardian. During the early parts of season one, Naru appeared quite often and spent much of her time with her best friend Usagi, but soon after the other Sailor Senshi were discovered, Usagi hasn't seen spending as much time with Naru as she used to, thus decreasing her screen time. Though Naru still made appearances, Usagi's friendship role with Naru was shifted towards the other Sailor Senshi.
Sailor Moon R
Gurio Umino later officially becomes her boyfriend. By the beginning of the Black Moon Clan saga of Pretty Soldier Sailor Moon R, she became a minor character. She may have figured out who Sailor Moon is. It's strongly hinted towards the end of the Black Moon Arc.
During the Cherry Blossom Festival, she, the Sailor Senshi, An (in disguise), Ms. Haruna, and Umino have a picnic. This is the first time she is seen hanging out with all the Sailor Senshi.
Sailor Moon S
In the third season, Umino and Naru began to have doubts about each other, with each one thinking the other was hiding something and possibly even dating someone else. Their relationship would be fixed after Naru and Umino participate in a couple's contest. Umino kept making embarrassing mistakes but after Umino makes a heartfelt speech, the couple wins the contest. However, the heart monument was implanted with a Daimon egg earlier, and when they touched it, it changed into a Daimon and attacks them, extracting Umino's Pure Heart, but they are saved by the Senshi.
Sailor Moon SuperS
Naru appears in the Sailor Moon Super S Special, Ami's First Love, along with Umino.
- In the DiC English dub, Naru (Molly in the dub) was given a strong Brooklyn accent.
- Both in the manga and Sailor Moon Crystal, Naru's eyes are blue. However, in the 90s anime, her eyes are teal.
- Naru was more of the main character in the early parts of season one. After the introduction of the Sailor Senshi, however, she was downgraded to a minor character until she was completely absent by the time of Stars.
- Before dating Umino, Naru looked down upon him because of his strange and geeky nature. By the third season, however, after dating for some time, Naru liked him. When Usagi made fun of Umino in front of Naru, Naru strongly defended him, saying he is a great guy.
- Naru has been a target (or within proximity of a target) of a villain in almost every season, except Stars.