Amulet Diamond

As a character with an intense shine, Amulet Dia's powers are mostly associated with stars and light. Due to Dia's power, this Character Transformation is used in case of absolute emergency.
She can use a small globe to harness a starry attack called "Starlight Navigation". In Chapter 38 of the manga, she uses two new attacks: "Twinkle Shield" and "Shooting Star Shower". In season three, Amu utilizes a new attack in this form called "Twinkle Hold", which has the power to capture (and supposedly cleanse) X-Eggs in a form of a sparkling sphere; and later uses "Open Heart" with Pure Feeling to purify them.

Amulet Clover

Since Amulet Clover's powers are domestic, she is mostly useful in defense and regeneration. She can also use this character's power to create food.
Amulet Clover can use a whisk for the attack "Remake Honey" to restore broken objects and purify X-Eggs. Later, they can also use an attack called "Remake Honey Special". On one occasion, she uses a harmless technique called "Sweet Applique" to create flowers and ribbons on Kairi's weapon. She is also able to generate a pan for defense.
In the second season, "Amulet Clover" utilizes a bubble wand. She uses it for "Honey Bubbles", which sends out a storm of bubbles to push off a horde of people and to clear off enemies' attacks. She later uses a bowl to absorb her opponent's attack and pepper to make her opponent sneeze.

Amulet Spade

Amulet Spade's abilities are centered around art and creativity, and are used in immobilizing the opponent and neutralizing attacks.
Amu wields a gigantic blue paintbrush to unleash the Colorful Canvas (カラフル キャンバス) and Colorful Canvas Special (カラフル キャンバス スペシャル) techniques, where a flood of multi-colored paint leaves the opponent immobilized. This technique is sometimes used in combination with Platinum Royale's White Decoration.
Instead of a painting brush, she utilizes a conductor's baton in the shape of a treble clef as a weapon in the second season. She uses Prism Music (プリズム ミュジック), an attack that sends multicolored notes to neutralize hypnosis and offensively.

Amulet Heart

As an athletic character, Amulet Heart's powers are mostly useful in combat.

In this form, she is able to jump to an incredible limit of heights and lengths. She uses pom-poms to act as shields or to deflect attacks, while her Heart Rod (ハート ロッド) is her main weapon. With it, she can perform the Spiral Heart (スパイラル ハート) and Spiral Heart Special (スパイラル ハート スペシャル) techniques, sprinkle a paralyzing pink energy over the target, and throw it like a boomerang.

Yaya Yuiki

Age:11
Height:157cm
Weight:41kg
Yaya Yuiki (結木やや, Yuiki Yaya) is the childish girl serving as the Ace's Chair and is one year junior to Amu. Yaya often acts immature for her age, such as having an enormous sweet tooth, a great soft spot for items like ribbons as well as tending to be hyperactive. Yaya wants to be a baby forever so her parents would give her more love than her younger brother. She is also a good ballerina, but also a rather clumsy one. Yaya's favorite things are cute and babyish.

Kairi Sanjou

Age:10
Height:160cm
Weight:50kg
Kairi is the younger brother of Yukari Sanjo and was sent to spy on the Guardians. This was not his choice though, Yukari immediately begged him to transfer to Seiyo upon discovering that he had a Guardian Character. Since his sister is busy at work, Kairi takes care of the household work (and his sister) in her apartment. However, when he saw the true meaning of his "missions," he tries to rebel against Yukari, but not before he reveals his secret to the Guardians when they accidentally discover him with Pestering CDs. After Amu convinces him that he needs to do what he truly thinks is right, he switches sides. After they stopped Easter's plan to use the Black Diamond CDs, he returns to his hometown and his place as the Jack's Chair is replaced by Nagihiko Fujisaki.

Rikka Hiiragi

Age:7
Height:130cm
Weight:34kg
Rikka Hiiragi has a high spunk and is an energetic character who always gets easily distracted whenever someone is talking to her. She is very kind and caring to poor things, for example, watering a plant in the sidewalk and saving a kitten from a tree. Ever since she first met Amu Hinamori and the Guardians, her dream goal was wanting to become a Guardian herself. Some days later, Rikka finally got what she dreamt for as she became a Guardian Apprentice, as well as Hikaru, and she is the current Queen's chair. She also takes care of X eggs because Rikka feels bad for them.

Ran
 Ran is almost always cheerful and encouraging, but since she doesn't have many abilities beyond her athletic skills, she is mostly seen cheering for her friends instead of helping. She sometimes uses random english like "yay!", and "go for it" when she cheers. She is also honest, as seen in her first character change with Amu. A very energetic and peppy character, she cannot seem to stay still for a long time

Miki
An artistic character, Miki is level-headed, calm and insightful. She is intuitive and seems to detect the presence of X-Eggs or Mystery Eggs better than her fellow Guardian Characters. She is also stubborn, disobediant and can be quite ironic at times, but overall she is very sensible and moderate.

Su
Su is very gentle and orderly, with a motherly attitude towards people who need her caring. But she can also be quite clumsy and ditzy at times. She is the one with the most interaction with Yuu Nikaidou after helping him clean his room. She has a fear for caterpillars, though she can get scared of anything relatively easy. Sometimes she can be over the top during cleaning jobs, ordering others around to help out

Dia
In her real form, she is still enigmatic and calm, but happy like an idol and wise. Her inner character seems to differ in the anime and manga. In the latest Shugo Chara! Chapter, it is hinted that Dia's character might be one like an "airhead", but in the anime, she expresses herself to be mature, only to be romantic and sassy on the inside

Yoru
Yoru is very mischievous and likes to taunt the Guardians and their Guardian Characters a lot. He especially likes to steal Kiseki's crown, and he also shown an interest in rapping. He also fights much with Il, Utan Hoshina's Guardian Character, but he usually loses. When he is around Ikuto, he usually ends up acting somewhat of a little brother to him. Yoru is often heard saying "nya" at the end of each sentence. Yoru is also selfless when need be, as he turned to the Guardians for help saving Ikuto when he couldn't do so on his own

Kiseki
As a person, he is very confident and egotistical, and thinks of the other Guardian Characters as "servants" and "commoners", who ignore him at times. He usually bosses other Guardian Characters around.

Hotaru
Hotaru is polite and elegant, providing a balance to Rikka's energy and spunk. She's open and able to get along with many people and Guardian Characters, who feel it'll be rude if they don't be polite to her. It is revealed in episode 22 of Party! that Hotaru is afraid of heights higher than her usual flying height. Hotaru also seems concerned about the fact that Rikka keeps so many X-eggs in her bedroom.

Musashi
Musashi encourages Kairi to do what he has to do. His looks and name are like a samurai. He is often the mature and calm Guardian Character which makes him seem much older that the others. He is very smart and sincere, much like his Bearer, Kairi. Musashi is level-headed, quick to respond, and very reasonalbe because he can see more than just one side of an argument, much like when Kairi did not want to follow his sister's orders and Musashi could understand why.

Pepe
Although babyish and immature, she shows a level of wit, particularly shown when she makes a dry comment at Kiseki. Pepe, like Yaya, always speaks in the third person. Pepe finishes each sentence with the phrase, "dechu" (desu) but since she is a baby that is her way of saying it.

Temari
Temari is mostly quiet and lady-like, but when something goes wrong, like when someone messes up the stage she and Nadeshiko dance in, or a rat appears in their house and makes her feel disrespectful, she character changes with Nadeshiko and becomes more aggressive and fierce-tempered, attacking with a naginata and speaks with a Hiroshima slang. Temari is also very well-mannered and in one of the earlier episodes, she tells Kiseki that she doesn't want to crawl on the floor because her kimono will get dirty. The Shugo Chara! Encyclopedia! describes Temari as very "ladylike" but "scary when she snaps.

KusuKusu
Kusukusu is a bubbly chara, who loves to smile and make people laugh, as well as performing random gags at random times. She loves to make weird faces at Rima to cheer her up when she is angry or mad, and gets disappointed when she does not smile. Kusukusu often is thrilled at the sound of Rima's laughter, even going out of her way to get many different people to help make Rima laugh in Episode 62.

Daichi
Like his owner, Daichi is very good at sports. He is an energetic, cheerful character and cannot seem to sit still.

Rhymth
He is born from Nagihiko's boyish self, so he is cool, outgoing, and a playboy(flirt). He is shown to like basketball, like Nagihiko when he was little. Rhythm is described to be friendly by Yaya, enthusiastic by Tadase, a flirt by Rima and one that acts impulsively by Nagihiko.