Kiseki is Tadase's Guardian Character. He looks like a mini Tadase with different-colored hair. He is extremely egotistical, loves to dominate, but also has tsundere characteristics. He is always trying to outshine Yoru. His bearing is that of typical "king's fashion", complete with crown and mantle. Kiseki also occasionally calls meetings that require all the Guardian Characters to gather. In volume one, Miki seems to have a crush on him, saying he is cool. Kiseki likes to give orders but does not like to obey. Suffers from pollen allergy like Tadase.

Kiseki can do Character Change with Tadase. When this happens, Tadase gains a golden crown and king’s scepter. The only reason he usually Character Changes is to help Tadase become confident and if Tadase is called "prince".

After the "Black Diamonds" incident, he became able to Character Transform with Tadase. Tadase becomes "Platinum Royale" and used the special skill "White Decoration", a skill thought to be a restoration skill.

Amu Hinamori is a 5th grade transfer student who is fashionably cool, tough and independent. Despite this, she is also a girl who seems unapproachable, both at home and at school. In reality, the "Cool and Spicy" role she plays is just a facade that she unconsciously plays. With her guardian characters, she fights the Easter Company who is extracting people's eggs to create X Eggs & X Characters in search of a special egg called the Embryo.
 
(Source: Crunchyroll)

Cousin of [Marina Massironi](https://anilist.co/staff/157944)

Everybody at Seiyo Elementary thinks that stylish and super cool Amu has it all: But nobody knows the real Amu, a shy girl who wishes she had the courage to truly be herself. Changing Amu&rsquo;s life is going to take more than wishes and dreams&ndash;it&rsquo;s going to take a little magic! One morning, Amu finds a surprise in her bed: three strange little eggs. Each egg contains a Guardian Character, an angel-like being who can give her the power to be someone new. With the help of her Guardian Characters, Amu is about to discover that her true self is even more amazing than she ever dreamed. 
(Source: Del Rey) 
Note: Includes 3 side stories.

With things having quieted down a bit for the Guardians, they can now focus on things besides fending off the peril of the evil Easter Corporation. Amu is having some troubles deciding which guy she likes the most, and hiding Ikuto in her room. Not only does the Embryo still elude the Guardians, and worries of Easter being suspiciously inactive, the threat of a new X Egg appears...

Amu meets a super-peppy transfer student at Seiyo Academy Elementary School named Hiiragi Rikka at school one day. Not only can she see Guardian Characters, but it seems she has some other, mysterious powers as well. When she sees the work that Amu and the other Guardians do at school, she's awestruck. 
Each 24-25 minute episode consists of a series of variety show style shorts (including Shugo Chara! Pucchi Puchi) totaling approx. 9-10 minutes, followed by the main 11-12 minute animation titled Shugo Chara!!! Dokki Doki which is the actual continuation of season 2 and comes with it's own opening animation. The remaining time is occupied by live action padding between each section and capped off with the opening/ending themes at the beginning and end of the episode. 
(Source: AniDB)

After graduating from Seiya Elementary School, Amu is ready to start junior high school. Amu is glad to be with her dear friends, but then she is asked to undertake a "secret mission" and has to transfer to a new school…?　A new adventure of Amu and Shugo Chara is about to begin! 
 
(Source: Comic Days, translated)

Amu's beloved Guardians Characters finally nab the spotlight in this new Shugo Chara series! Ran, Miki, and Su explore holidays, exercise, bears, cooking, painting, and more character changes than you can count in these hilarious and lighthearted short stories, told in 4-koma (4-panel) comic-strip format.
 (Source: Kodansha USA)