She is one of Stitch's best friends and his caretaker after Stitch runs off to Izayoi Island on Stitch!. After a few shenanigans, the two became best friends with a pinky swear. Yuna's personality comes off as kind, polite and sweet at first; but she can turn feisty, defensive and angry if she spots something she doesn't like, like evil, bullying, crime or the like. She also can be very confident and overbearing at times, often taking charge into situations when needed, and acting without thinking. With her being a blackbelt, she uses her karate skills as a way to help her loved ones, not hurt them; and will use her karate skills to fight and defend herself and others. Yuna also has a playful yet competitive side to her personality, often playfighting or competing with her friends, Stitch included; usually just for fun, but it can go beyond if she's devoted enough. She also has an attitude that shows quite often too, often shown through jealousy or wit.
However, despite her personality, she does have a limit to her emotional side, and while she does keep her emotions to herself (in a way not to let anyone worry), she can break down or act up if enough pressure is on her, coming between either yelling or acting out of anger, or crying and resenting when frustrated or in despair. But with help from her friends and Stitch, she often gets better.
The other majority of her family are elsewhere, with her father is out at work a lot as a marine biologist around Okinawa, and her mother died when she was an infant in a typhoon. Her life remained normal yet happy until one day, after a varied coincidence, she meets a strange creature that came crashlanding from the Turo system of outer space, Experiment 626, or as we know him, Stitch. From then and there when they met, the two became best friends and the duo go on various adventures on Stitch's quest in order to do good deeds and gain a wish from the island's mystical Spiritual Stone.
Yuna though, throughout the majority of the anime, finds friends like Taro, Sae, JJ, Tonbo, yokai like Kijimunaa, and even in Experiments like Angel. However, her strong sense of justice is what makes her a tomboy, and that shows against evildoers like Dr. Hamsterviel, and against rivals like Penny and her gang of bullies. She shifts between a nice and sweet personality to fierce and feisty if danger or whatever approaches.
Yuna shows a few recurring traits with her character, beyond the factor of being a blackbelt of karate. One is the potential favorite animal of a porpoise, as told from the plushie in her room (aka "Puff the Powder Blue Porpoise") and from an inflatable beach toy she owns. In addition, some of Yuna's potential favorite foods as well include corn-on-the-cob, sugarcane and mochi, telling from a few occasions in the anime. She also has a fond nature to make promises with her friends via pinky swears. Another trait is that from her appearance, which despite her look, she seems to have large cheeks, something she detests upon: this is noticably shown when Yuna is pouting or whilst breathholding. A third is that Yuna isn't good at mathematics, often getting low or abysmal scores on math tests at her school. One last thing is that Yuna has a fear of thunder and lightning which she tries to cover up, as she stands by the firm belief that karate masters are "never scared."
The creators of the anime got Yuna's name from the Japanese name of sea hibiscus out in Okinawa (known in Japanese as Yuna). Yuna's birthday is on February 25th. Yuna's last name of Kamihara wasn't unveiled until much later, although previous guesses were Chitama, after the dojo, forest and town on Izayoi and Hanako, which was Yuna's previous name and design during development of the anime.
- In the English dub, when Remmy shows Yuna the memory of her mother humming a tune to her when she was a baby, the tune she is humming is "Baby Mine" from the Disney movie Dumbo. The sequences are very similar, as it shows Dumbo's mother cradling her calf in her trunk.
- The English dub states that in one episode Yuna's age was 9, but later 12 in another episode in line before Stitch! ~Zutto Saiko no Tomodachi~. However, this age flux is actually an English dub error, as the Japanese original states on many an occasion that Yuna is 10 for the first series and then in Stitch! ~Zutto Saiko no Tomodachi~, 11 rounded off. Knowing this, the episode "Stitch's Surprise Party" has Yuna turn 10 and remain so for the entirety of the first series. Also, a later Zutto episode, "Stitch's Dreams", has Yuna turn a proper 12 following her move to New Town at 11, respectively.