Yaya Yuiki is a ten year old girl in elementary school who dreams of being a sweet baby for the rest of her life. She is also one of the main supporting characters.
BackgroundYaya is the youngest of the Guardians and she serves as the Ace's Chair. She is very childish so it's quite a shock to see her acting serious. Amu and Tadase were surprised to see her act serious and brave on the season finale of season two when she promised them that she would hold off the X Eggs while they escaped to go save Ikuto. After seeing the shocked expression on their faces, she cried and screamed at them for never taking her seriously, and that she could be serious if she wanted to. Amu and Tadase promtly apologized before leaving to go save Ikuto.
Even though she is childish, Yaya takes responsibility whenever it's handed to her. Although she may be scared, she continues to walk on in order not to let her friends, the Guardians, down. Thankfully, she has the help and support of her fellow Guardians.
Yaya's dream is to be a baby for the rest of her life, but she obviously can't do that since she keeps aging, and not only that, she also has a new baby brother, making her the older sister and not the baby of the family. When her baby brother was born, Yaya barely spent time with him, and never took care of him because she blames him for making her parents pay more attention to him than her. However, because she never took care of him, she went into a crisis when her parents went away on a trip and she didn't know how to take care of the baby. Thankfully, her friends helped her through it, and she bonded with her baby brother, causing her to not hate him anymore. Now she loves her little brother and likes to hang out with him.
To keep herself "baby-like," Yaya constantly cries and eats sweets. Because of this, Yaya's job in the Guardians is believed to be just to eat sweets. However, it was revealed in one episode that she does just as much work as everyone else, and was jealous of Amu because Amu was never assigned any work. Even though she does all this work, she certainly doesn't do it without complaints. After finishing her work every day, she will whine like a baby and cry for sweets and fun.
The only time Yaya seems to be serious is when she is dancing ballet. Ballet is her one true passion and she practices it every day after school at a dance studio. She is very graceful when she dances, and she seems to try more than the rest of the class to be elegant while dancing. She was even placed as the lead role in a dance recital because the lead twisted her ankle. However, after learning of Yaya's promotion, the former lead did all she can to mark down Yaya's self esteem by telling her that she could never dance as gracefully as she could, and that she was too clumsy. However, Yaya was very determined, and used these insults as motivation to become better. In the end, Yaya perfected the dance and performed as the lead in front of a large audience at a dance recital. Her friends watched her proudly, her crush, Kukai, cried at how elegant she was, and the former lead finally accepted that Yaya was a good dancer, just "not as good as her."
Since Yaya is the youngest of the Guardians, she had to stay behind when everyone else graduated. She was to form the new Guardians with herself as the Ace's Chair, Rikka as the Queen's Chair, and Hikaru as the King's Chair. She wished them luck and swore that she would be a good leader to the Guardians before joining them in middle school next year. But until that day came, Yaya proudly wore her status as the oldest of the guardians, since she had always been the youngest before. She swore to watch over them and be a good leader to them as well.
In the last chapter of Shugo Chara encore, Yaya had the smallest part. She only had one line throughout the whole chapter, and that was right before Kairi was about to confess to Amu. He started to say "Amu...I...really...for the longest time, I've always...!" but before he could finish, Yaya teased him by saying, "wanted to eat sushi with you." which blocked him from saying his confession, and from Amu ever hearing his confession in the manga.
PepePepe is Yaya's only shugo chara and she represents Yaya's dream to be a baby.
Pepe takes on the appearance of a baby, wearing a one-piece pajama set and always sucking on a pacifier. She also ends all of her sentences with "dechu."
Pepe has the exact same personality as Yaya, because unlike all the other Guardians, Yaya doesn't hide her true self, she acts the way she wants to. Even when Yaya chara-changes, her personality doesn't change at all. The only thing that happens during a chara-change is that Yaya gains a bib around her neck and she normally starts crying or whining over something she can't have. While Yaya whines, Pepe often wines with her, lashing around in an identical way to Yaya.
Dear BabyWhen Yaya transforms with Pepe, she becomes Dear Baby.
When Yaya becomes Dear Baby, she wears an outfit almost exactly like Pepe's. She wears a one-piece pajama suit and wears a bib as well. She also has a hat with large bunny ears on it and booties that resemble rabbit feat.
Since Yaya is the weakest of the Guardians, her attacks are pretty weak to. Her special attack is "Go! Go! Little Duckies!" where she makes fifty rubber ducks appear and fly at the opponent, however, this attack as never succeded. So during battles, Yaya is always the one who stands on the sidelines and barely does anything except perform failed attempts at attacks.
However, when Yaya chara-changes, she does gain two weapons (either is her choice). The first is a giant rattle which she swings at her opponent to injure them. The next is a giant bottle in which she blasts warm milk from. Either of these attacks can be successful, but they barely do anything since they are such weak attacks.
Yaya can even attack herself accidently. One of her attacks is to release a mobile of duckies to put her opponent to sleep. However, this often backfires and causes her and Pepe to fall asleep inside.
Because of her weak attacks and cowardly nature, Yaya could barely contribute in the finale of the second season when they all went to rescue Ikuto. Yaya promised to hold off the X Eggs for as long as she could, but failed miserably because she is so weak. Thankfully, Utau showed up, and Yaya inlisted in her help. Utau gladly oblidged because they were both "little sister types," and they needed to stick together. Utau then promtly purified all the X Eggs so Yaya wouldn't have to fight them anymore.
- Amu Hinamori: Like everyone else in the Guardians, Amu is a close friend of Yaya's, and is seen numerous times hanging out with her along with the girls of the Guardians. Yaya is the only girl-friend of Amu's in the Guardians that has stayed with her since the beginning of the series, since Nadeshiko left in the first season, and Rima didn't come in until the second half of the first season. Amu is often the one to calm Yaya down after she has her whining attacks. Yaya also refers to Amu by a pet name, Amu-chi.
- Tadase Hotori: Like everyone else in the Guardians, Tadase is a close friend of Yaya's.
- Nadeshiko/Nagihiko: Like everyone else in the Guardians, Nagihiko is a good friend of Yaya's. However, Yaya, along with Amu, are the only Guardians who don't know Nagihiko's secret, and still believe him to be Nadeshiko's twin brother.
- Rima Mashiro: Rima is Yaya's best friend and they are both seen constantly gossiping to each other about Amu and Tadase's romantic relationship. Although they have conflicting personalities, and Rima thought Yaya was annoying at first, they soon grew to be friends. Yaya, because she is the comic relief, tries her hardest to make Rima smile and be happy, which may be why they're so close.
- Kairi Sanjo: Kairi and Yaya never really talked to each other throughout the series, however, in the third chapter of Shugo Chara encore, Kairi and Yaya end up meeting and hanging out, they even entered a contest together to win a bunch of flowers. This chapter showed their friendship beginning to form.
Love Life:Kukai Souma: Kukai and Yaya were the closest to each other in the Guardians and were always seen hanging out with each other alone, just like how Tadase and "Nadeshiko" always hung out together alone. Kukai and Yaya also have many things in common such as goofing off and not doing any work. Kukai also is the one who cheers up Yaya when she's feeling down and was seen playing with Yaya numerous times.
When Kukai went to go see Yaya at her ballet recital, he was seen crying and mumbling about how elegant she was.
When Kukai left for middle school, Yaya cried and clung on to his arm, begging him not to go. Kukai comforted her then gave her one last hug, when he did this, a faint blush could be seen on Yaya's cheeks. When Kukai visits every now and then from middle school, Yaya becomes really excited and hugs him, telling him that she missed him. Kukai would then smile at her and hug her before making a joke and laughing it over with her.
Kukai obviously doesn't have a problem with Yaya clinging onto him and hugging him, and he would gladly do so back to her, in fact, he has. Kukai as been seen numerous times holding her hand as he leads her off, or hugging her after not seeing her for awhile.
- The only time Yaya has her hair down is when she's transforming. All other time she is shown, her hair is always tied into pigtails.
- Yaya is the only Guardian, other than Tadase and Amu, who has stayed in the Guardians throughout the entire series.
- Yaya is a big fan of Utau's, and she goes to see her concerts frequently.
- Yaya was one of the last Guardians to get a character transformation, she was also one of the last to get her transformation upgraded.
- Yaya is the only one of the Guardians, other than Amu, who doesn't know Nagihiko's secret.
- Yaya's favorite colors are baby blue, yellow, and pink.
- In the finale of Shugo Chara Encore, Yaya had the smallest part. Even though she was one of the main characters, she only had one line throughout the entire chapter.